subject:(Soot turbulence chemistry interactions)

Penn State University

1. Mehta, Ranjan S. Detailed Modeling of Soot Formation and Turbulence – Radiation Interactions in Turbulent Jet Flames .

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/9256

► Detailed radiation modeling of turbulent sooting flames faces a number of challenges. Principal among these have been been a lack of good models for predicting… (more)

▼ Detailed radiation modeling of turbulent sooting flames faces a number of challenges. Principal among these have been been a lack of good models for predicting soot formation and effective means to capture turbulence – chemistry interactions in soot subprocesses. Uncertainties in measurement and prediction of soot properties has also been a problem. Radiative heat transfer becomes important in combustion environments due to the very high temperatures encountered and has not yet been studied in sufficient detail in the case of luminous (i.e., sooting) flames. A comprehensive approach for modeling turbulent reacting flows, including detailed chemistry, radiation and soot models with detailed closures for turbulence – chemistry interactions (TCI) and turbulence – radiation interactions (TRI) is developed in this work. A review of up-to-date literature on turbulent combustion modeling, turbulence-radiation interactions and soot modeling is given. A transported probability density function (PDF) approach is used to model turbulence – chemistry interactions and extended to include soot formation. Nongray gas and soot radiation is modeled using a photon Monte Carlo (PMC) method coupled with the PDF method. Soot formation is modeled based on the method of moments (MOM) approach with interpolative closure. Optimal soot submodel parameters are identified based on comparison of model predictions with experimental data from various laminar premixed and (opposed) diffusion flames. These parameters (including gas-phase chemistry) are applied to turbulent flames without further ``tuning.' Six turbulent jet flames with Reynolds numbers varying from 6700 to 15000, varying fuel types – pure ethylene, 90% methane-10% ethylene blend and different oxygen concentrations in the oxidizer stream from 21% O2 (air) to 55% O2, are simulated. The predicted soot volume fractions, temperature and radiative wall fluxes (when available) are compared with experiments. All the simulations are carried out with a single set of parameters for all models involved, without specific adjustments. Very encouraging agreement is found for most of the quantities, representing a significant step forward in modeling turbulent sooting flames. A detailed analysis of the radiation characteristics of these flames is also undertaken. It is found that emission TRI was generally important for all the flames. In the laboratory scale flames, including TRI increases the radiative loss from the flame by up to 90%. Absorption TRI is found to be unimportant in laboratory-scale flames, but becomes important in the large (industrial scale) flame that was studied numerically. Advisors/Committee Members: Michael F Modest, Committee Chair/Co-Chair, Daniel Connell Haworth, Committee Chair/Co-Chair, Stephen R Turns, Committee Member, Padma Raghavan, Committee Member, Karen Ann Thole, Committee Member.

Subjects/Keywords: Combustion; Turbulent Flames; Radiation; Soot Formation; PDF Methods; Turbulence-Radiation Interactions; Turbulence-Chemistry Interactions; Method of Moments

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Mehta, R. S. (2008). Detailed Modeling of Soot Formation and Turbulence – Radiation Interactions in Turbulent Jet Flames . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/9256

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Mehta, Ranjan S. “Detailed Modeling of Soot Formation and Turbulence – Radiation Interactions in Turbulent Jet Flames .” 2008. Thesis, Penn State University. Accessed January 27, 2021. https://submit-etda.libraries.psu.edu/catalog/9256.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Mehta, Ranjan S. “Detailed Modeling of Soot Formation and Turbulence – Radiation Interactions in Turbulent Jet Flames .” 2008. Web. 27 Jan 2021.

Vancouver:

Mehta RS. Detailed Modeling of Soot Formation and Turbulence – Radiation Interactions in Turbulent Jet Flames . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Jan 27]. Available from: https://submit-etda.libraries.psu.edu/catalog/9256.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Mehta RS. Detailed Modeling of Soot Formation and Turbulence – Radiation Interactions in Turbulent Jet Flames . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/9256

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

2. Burot, Daria. Transported probability density function for the numerical simulation of flames characteristic of fire : Méthode de transport de la fonction densité de probabilité pour la modélisation des flammes caractéristiques des incendies.

Degree: Docteur es, Energétique, 2017, Aix Marseille Université

URL: http://www.theses.fr/2017AIXM0026

►

La simulation de scenarios d’incendie nécessite de modéliser de nombreux processus complexe, particulièrement la combustion gazeuse d’hydrocarbure incluant la production de suie et les transferts… (more)

▼

La simulation de scenarios d’incendie nécessite de modéliser de nombreux processus complexe, particulièrement la combustion gazeuse d’hydrocarbure incluant la production de suie et les transferts radiatifs dans un écoulement turbulent. La nature turbulente de l’écoulement fait apparaitre des interactions qui doivent être prises en compte entre ces processus. L’objectif de cette thèse est d’implémenter une méthode de transport de la fonction de densité de probabilité afin de modéliser ces interactions de manière précise. En conjonction avec un modèle de flammelettes, le modèle de Lindstedt et un modèle à large-bande k-corrélé, l’équation de transport de la PDF jointe de composition est résolue avec la méthode des Champs Eulérien Stochastiques. Le modèle est validé en simulant 12 flammes turbulentes recouvrant une large gamme de nombre de Reynolds et de propension à former de la suie par les combustibles. Dans un second temps, les effets des interactions rayonnement-turbulence (TRI) sur l’émission de la suie sont étudiés en détails, montrant que la TRI tend à augmenter l’émission radiative de la suie à cause des fluctuations de température, mais que cette augmentation est plus faible pour des nombres de Reynolds élevés ou des quantités de suie plus élevées. Ceci est dû à la corrélation négative entre le coefficient d’absorption des suies et la fonction de Planck. Finalement, l’influence de la corrélation entre la fraction de mélange et le paramètre de non-adiabaticité est étudiée sur une flamme d’éthylène, montrant qu’elle a peu d’effet sur la structure moyenne de flamme mais tend à limiter les fluctuations de température et les pertes radiatives.

The simulation of fire scenarios requires the numerical modeling of various complex process, particularly the gaseous combustion of hydrocarbons including soot production and radiative transfers in a turbulent. The turbulent nature of the flow induces interactions between these processes that need to be taken accurately into account. The purpose of this thesis is to implement a transported Probability Density function method to model these interactions precisely. In conjunction with the flamelet model, the Lindstedt model, and a wide-band correlated-k model, the composition joint-PDF transport equation is solved using the Stochastic Eulerian Fields method. The model is validated by simulating 12 turbulent jet flames covering a large range of Reynolds numbers and fuel sooting propensity. Model prediction are found to be in reasonable agreement with experimental data. Second, the effects of turbulence-radiation interactions (TRI) on soot emission are studied in details, showing that TRI tends to increase soot radiative emission due to temperature fluctuations, but that this increase is smaller for higher Reynolds numbers and higher soot loads. This is due to the negative correlation between soot absorption coefficient and the Planck function. Finally, the effects of taking into account the correlation between mixture fraction and enthalpy defect on flame structure and…

Advisors/Committee Members: Consalvi, Jean-Louis (thesis director).

Subjects/Keywords: Méthode de transport de la PDF; Champs Eulériens stochastiques; Interactions suies/turbulence; Rayonnement/turbulence; Rayonnement/combustion; Transported PDF method; Stochastic Eulerian field; Turbulence-Soot production interactions; Turbulence-Radiation interactions; Combustion-Radiation interactions.

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Burot, D. (2017). Transported probability density function for the numerical simulation of flames characteristic of fire : Méthode de transport de la fonction densité de probabilité pour la modélisation des flammes caractéristiques des incendies. (Doctoral Dissertation). Aix Marseille Université. Retrieved from http://www.theses.fr/2017AIXM0026

Chicago Manual of Style (16^th Edition):

Burot, Daria. “Transported probability density function for the numerical simulation of flames characteristic of fire : Méthode de transport de la fonction densité de probabilité pour la modélisation des flammes caractéristiques des incendies.” 2017. Doctoral Dissertation, Aix Marseille Université. Accessed January 27, 2021. http://www.theses.fr/2017AIXM0026.

MLA Handbook (7^th Edition):

Burot, Daria. “Transported probability density function for the numerical simulation of flames characteristic of fire : Méthode de transport de la fonction densité de probabilité pour la modélisation des flammes caractéristiques des incendies.” 2017. Web. 27 Jan 2021.

Vancouver:

Burot D. Transported probability density function for the numerical simulation of flames characteristic of fire : Méthode de transport de la fonction densité de probabilité pour la modélisation des flammes caractéristiques des incendies. [Internet] [Doctoral dissertation]. Aix Marseille Université 2017. [cited 2021 Jan 27]. Available from: http://www.theses.fr/2017AIXM0026.

Council of Science Editors:

Burot D. Transported probability density function for the numerical simulation of flames characteristic of fire : Méthode de transport de la fonction densité de probabilité pour la modélisation des flammes caractéristiques des incendies. [Doctoral Dissertation]. Aix Marseille Université 2017. Available from: http://www.theses.fr/2017AIXM0026

Penn State University

3. Kung, Eugene Hans. PDF-Based Modeling of Autoignition and Emissions for Advanced Direct-Injection Engines .

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/9266

► Transported probability density function (PDF) methods have shown promise in modeling canonical flame configurations. More recently, they have been applied to simple engine configurations to… (more)

▼ Transported probability density function (PDF) methods have shown promise in modeling canonical flame configurations. More recently, they have been applied to simple engine configurations to demonstrate their feasibility in more practical applications, and to demonstrate the importance of accurate accounting for turbulence/chemistry interactions (TCI) in IC engines. The research conducted here advances the state-of-the-art in two areas: advanced physical models and numerical methods for multiphase chemically reacting turbulent flows; and advanced combustion systems for direct-injection diesel engines. The hypotheses that are tested in this thesis are that turbulent fluctuations significantly impact heat release and emissions in advanced diesel engines and that PDF methods capture TCI effects in real engines. Contributions to modeling and algorithms include: 1) liquid fuel spray/PDF coupling; 2) ``real engine" applications of PDF particle tracking through complex meshes; and 3) modularization of coupling among detailed thermochemistry and PDF methods. Contributions to engine combustion have included: 1) multiple-cycle calculations; 2) modeled premixed/direct-injection splits; 3) insight into the roles of turbulence and TCI on autoignition and emissions; 4) detailed information from the PDF method including spatial non-homogeneity, fluctuation effects, NOx and soot prediction, and detailed speciation; and 5) quantitative comparisons between CFD and experiment for a real engine. This research shows that turbulence/chemistry interactions in real engine applications are important to understanding and modeling engine combustion. The work allows for better analysis and performance prediction of advanced engine designs and points to how the models may be improved. Already, the PDF model's application to the real engine case here has shown appreciably better robustness and quantitative accuracy in ignition and emissions predictions compared to a conventional finite-volume approach where TCI is not considered. Ignition timing, heat release, and emissions are captured favorably with the PDF method. Directions for future improvement and research are suggested to address the remaining modeling issues. Advisors/Committee Members: Andre Louis Boehman, Committee Member, Domenic Adam Santavicca, Committee Member, Stephen R Turns, Committee Member, Daniel Connell Haworth, Committee Chair/Co-Chair.

Subjects/Keywords: Emissions Modeling; Internal Combustion Engine; PDF Method; NOx; CO; Hydrocarbon; Soot; Turbulence/Chemistry Interactions

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kung, E. H. (2008). PDF-Based Modeling of Autoignition and Emissions for Advanced Direct-Injection Engines . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/9266

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kung, Eugene Hans. “PDF-Based Modeling of Autoignition and Emissions for Advanced Direct-Injection Engines .” 2008. Thesis, Penn State University. Accessed January 27, 2021. https://submit-etda.libraries.psu.edu/catalog/9266.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kung, Eugene Hans. “PDF-Based Modeling of Autoignition and Emissions for Advanced Direct-Injection Engines .” 2008. Web. 27 Jan 2021.

Vancouver:

Kung EH. PDF-Based Modeling of Autoignition and Emissions for Advanced Direct-Injection Engines . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Jan 27]. Available from: https://submit-etda.libraries.psu.edu/catalog/9266.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kung EH. PDF-Based Modeling of Autoignition and Emissions for Advanced Direct-Injection Engines . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/9266

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

4. Zhang, Hedan. Effects of turbulence-chemistry interactions in direct-injection compression-ignition engines.

Degree: 2012, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/16172

► Advanced combustion strategies are emphasized in modern compression-ignition engine systems, aiming at improving diesel engine efficiency and reducing pollutant emissions, especially soot and NOx, together… (more)

Subjects/Keywords: turbulence-chemistry interactions; probability density function; diesel engine; NOx; n-heptane

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Zhang, H. (2012). Effects of turbulence-chemistry interactions in direct-injection compression-ignition engines. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/16172

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Zhang, Hedan. “Effects of turbulence-chemistry interactions in direct-injection compression-ignition engines.” 2012. Thesis, Penn State University. Accessed January 27, 2021. https://submit-etda.libraries.psu.edu/catalog/16172.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Zhang, Hedan. “Effects of turbulence-chemistry interactions in direct-injection compression-ignition engines.” 2012. Web. 27 Jan 2021.

Vancouver:

Zhang H. Effects of turbulence-chemistry interactions in direct-injection compression-ignition engines. [Internet] [Thesis]. Penn State University; 2012. [cited 2021 Jan 27]. Available from: https://submit-etda.libraries.psu.edu/catalog/16172.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Zhang H. Effects of turbulence-chemistry interactions in direct-injection compression-ignition engines. [Thesis]. Penn State University; 2012. Available from: https://submit-etda.libraries.psu.edu/catalog/16172

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

5. Donde, Pratik Prakash. LES/PDF approach for turbulent reacting flows.

Degree: PhD, Aerospace Engineering, 2012, University of Texas – Austin

URL: http://hdl.handle.net/2152/19481

► The probability density function (PDF) approach is a powerful technique for large eddy simulation (LES) based modeling of turbulent reacting flows. In this approach, the… (more)

▼ The probability density function (PDF) approach is a powerful technique for large eddy simulation (LES) based modeling of turbulent reacting flows. In this approach, the joint-PDF of all reacting scalars is estimated by solving a PDF transport equation, thus providing detailed information about small-scale correlations between these quantities. The objective of this work is to further develop the LES/PDF approach for studying flame stabilization in supersonic combustors, and for soot modeling in turbulent flames. Supersonic combustors are characterized by strong shock-turbulence interactions which preclude the application of conventional Lagrangian stochastic methods for solving the PDF transport equation. A viable alternative is provided by quadrature based methods which are deterministic and Eulerian. In this work, it is first demonstrated that the numerical errors associated with LES require special care in the development of PDF solution algorithms. The direct quadrature method of moments (DQMOM) is one quadrature-based approach developed for supersonic combustion modeling. This approach is shown to generate inconsistent evolution of the scalar moments. Further, gradient-based source terms that appear in the DQMOM transport equations are severely underpredicted in LES leading to artificial mixing of fuel and oxidizer. To overcome these numerical issues, a new approach called semi-discrete quadrature method of moments (SeQMOM) is formulated. The performance of the new technique is compared with the DQMOM approach in canonical flow configurations as well as a three-dimensional supersonic cavity stabilized flame configuration. The SeQMOM approach is shown to predict subfilter statistics accurately compared to the DQMOM approach. For soot modeling in turbulent flows, an LES/PDF approach is integrated with detailed models for soot formation and growth. The PDF approach directly evolves the joint statistics of the gas-phase scalars and a set of moments of the soot number density function. This LES/PDF approach is then used to simulate a turbulent natural gas flame. A Lagrangian method formulated in cylindrical coordinates solves the high dimensional PDF transport equation and is coupled to an Eulerian LES solver. The LES/PDF simulations show that soot formation is highly intermittent and is always restricted to the fuel-rich region of the flow. The PDF of soot moments has a wide spread leading to a large subfilter variance. Further, the conditional statistics of soot moments conditioned on mixture fraction and reaction progress variable show strong correlation between the gas phase composition and soot moments. Advisors/Committee Members: Raman, Venkat (advisor), Clemens, Noel (committee member), Ezekoye, Ofodike (committee member), Goldstein, David (committee member), Moser, Robert (committee member).

Subjects/Keywords: Probability density function approach; Large eddy simulation; Supersonic combustion modeling; Soot modeling; Turbulent reacting flows; Direct quadrature method of moments; Semi-discrete quadrature method of moments; Quadrature based methods; Lagrangian Monte Carlo methods; Supersonic combustors; Flame stabilization; Polycyclic aromatic hydrocarbons; Soot-turbulence-chemistry interactions; Shock-turbulence-chemistry interactions

…This approach towards modeling turbulence-chemistry interactions is computationally… …turbulence-chemistry interactions. While the LES/PDF approach is well suited for describing these… …Chapter 5. Soot modeling in turbulent flames 5.1 Gas-phase chemistry… …of soot precursors, turbulence-related strain, and combustion processes are critical in… …complex interactions between the gas-phase composition, soot particles and the turbulent flow…

10 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Donde, P. P. (2012). LES/PDF approach for turbulent reacting flows. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/19481

Chicago Manual of Style (16^th Edition):

Donde, Pratik Prakash. “LES/PDF approach for turbulent reacting flows.” 2012. Doctoral Dissertation, University of Texas – Austin. Accessed January 27, 2021. http://hdl.handle.net/2152/19481.

MLA Handbook (7^th Edition):

Donde, Pratik Prakash. “LES/PDF approach for turbulent reacting flows.” 2012. Web. 27 Jan 2021.

Vancouver:

Donde PP. LES/PDF approach for turbulent reacting flows. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2012. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/2152/19481.

Council of Science Editors:

Donde PP. LES/PDF approach for turbulent reacting flows. [Doctoral Dissertation]. University of Texas – Austin; 2012. Available from: http://hdl.handle.net/2152/19481

University of Toronto

6. Halmo, James Christopher. Study of Turbulent Swirl-stabilized Non-premixed Ethylene Flames in a Model Combustor.

Degree: 2014, University of Toronto

URL: http://hdl.handle.net/1807/68050

►

The study of turbulent swirl-stabilized non-premixed flames in a model combustor is needed to improve the understanding of flow characteristics and soot production in aero-engines.… (more)

Subjects/Keywords: Combustion; Laser-Induced Incandescence; Particle Image Velocimetry; Soot; Turbulence; 0538

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Halmo, J. C. (2014). Study of Turbulent Swirl-stabilized Non-premixed Ethylene Flames in a Model Combustor. (Masters Thesis). University of Toronto. Retrieved from http://hdl.handle.net/1807/68050

Chicago Manual of Style (16^th Edition):

Halmo, James Christopher. “Study of Turbulent Swirl-stabilized Non-premixed Ethylene Flames in a Model Combustor.” 2014. Masters Thesis, University of Toronto. Accessed January 27, 2021. http://hdl.handle.net/1807/68050.

MLA Handbook (7^th Edition):

Halmo, James Christopher. “Study of Turbulent Swirl-stabilized Non-premixed Ethylene Flames in a Model Combustor.” 2014. Web. 27 Jan 2021.

Vancouver:

Halmo JC. Study of Turbulent Swirl-stabilized Non-premixed Ethylene Flames in a Model Combustor. [Internet] [Masters thesis]. University of Toronto; 2014. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/1807/68050.

Council of Science Editors:

Halmo JC. Study of Turbulent Swirl-stabilized Non-premixed Ethylene Flames in a Model Combustor. [Masters Thesis]. University of Toronto; 2014. Available from: http://hdl.handle.net/1807/68050

7. Guenel, Mathieu. Dissipation de marée dans les étoiles de faible masse et les planètes géantes : ondes inertielles, structure interne et rotation différentielle : Tidal dissipation in low-mass stars and giant planets : inertial waves, internal structure and differential rotation.

Degree: Docteur es, Astronomie et Astrophysique, 2016, Université Paris-Saclay (ComUE)

URL: http://www.theses.fr/2016SACLS307

►

Cette thèse étudie les mécanismes de dissipation de marée dans les étoiles de faible masse, possédant comme notre Soleil une enveloppe convective externe (i.e. de… (more)

▼

Cette thèse étudie les mécanismes de dissipation de marée dans les étoiles de faible masse, possédant comme notre Soleil une enveloppe convective externe (i.e. de types M à F), ainsi que dans les planètes géantes gazeuses similaires à Jupiter et Saturne. En particulier, nous cherchons à comprendre et à caractériser l’influence de la structure et de la dynamique internes de ces corps sur les différents mécanismes physiques à l’origine de cette dissipation afin d’évaluer leur importance relative.Dans le cas des planètes géantes, nous utilisons des modèles semi-analytiques préexistants et nous montrons que la dissipation induite par la présence éventuelle d’un cœur solide viscoélastique n’est pas négligeable par rapport à celle induite par les ondes inertielles (dont la force de rappel est l’accélération de Coriolis) dans l’enveloppe convective. Pour les étoiles de faible masse, nous développons de nouvelles méthodes semi-analytiques ainsi que des simulations numériques d’ondes inertielles de marée se propageant dans l’enveloppe convective externe, dont nous calculons et caractérisons la dissipation d’énergie associée. Pour la première fois, nous prenons en compte les effets d’une rotation différentielle latitudinale telle qu’observée dans le Soleil et prédite par de nombreuses simulations numériques de convection dans les étoiles de faible masse. Nous mettons en évidence l’existence de nouvelles familles de modes inertiels ainsi que l’importance des résonances de corotation pour la dissipation de marée. Enfin, nous dérivons une nouvelle prescription pour la viscosité turbulente appliquée à ces ondes de marées en prenant en compte l’influence de la rotation sur les propriétés de la convection le long de l’évolution des étoiles.

This thesis studies the tidal dissipation mechanisms in low-mass stars that have an external convective envelope like the Sun (i.e. from M- to F-type stars), as well as in Jupiter- and Saturn-like gaseous giant planets. We particularly focus on understanding and characterizing the influence of the internal structure and dynamics of these bodies on the various physical mechanisms that cause this tidal dissipation, in order to assess their relative strength.In the case of giant planets, we use preexisting semi-analytical models and we show that the dissipation induced by the possible presence of a viscoelastic solid core is not negligible compared to the one induced by inertial waves (whose restoring force is the Coriolis acceleration) in the convective envelope. For low-mass stars, we perform a new semi-analytic study as well as numerical simulations of tidal inertial waves propagating in the external convective envelope, and we compute the associated energy dissipation. For the first time, the effects of a background latitudinal differential rotation, as observed in the Sun and predicted by various numerical simulations of convection in low-mass stars, is taken into account. We highlight the existence of new families of inertial modes as well as the importance of corotation resonances for…

Advisors/Committee Members: Mathis, Stéphane (thesis director).

Subjects/Keywords: Marées; Hydrodynamique; Ondes; Turbulence; Interactions étoile-Planète; Tides; Hydrodynamics; Waves; Turbulence; Star-Planet interactions

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Guenel, M. (2016). Dissipation de marée dans les étoiles de faible masse et les planètes géantes : ondes inertielles, structure interne et rotation différentielle : Tidal dissipation in low-mass stars and giant planets : inertial waves, internal structure and differential rotation. (Doctoral Dissertation). Université Paris-Saclay (ComUE). Retrieved from http://www.theses.fr/2016SACLS307

Chicago Manual of Style (16^th Edition):

Guenel, Mathieu. “Dissipation de marée dans les étoiles de faible masse et les planètes géantes : ondes inertielles, structure interne et rotation différentielle : Tidal dissipation in low-mass stars and giant planets : inertial waves, internal structure and differential rotation.” 2016. Doctoral Dissertation, Université Paris-Saclay (ComUE). Accessed January 27, 2021. http://www.theses.fr/2016SACLS307.

MLA Handbook (7^th Edition):

Guenel, Mathieu. “Dissipation de marée dans les étoiles de faible masse et les planètes géantes : ondes inertielles, structure interne et rotation différentielle : Tidal dissipation in low-mass stars and giant planets : inertial waves, internal structure and differential rotation.” 2016. Web. 27 Jan 2021.

Vancouver:

Guenel M. Dissipation de marée dans les étoiles de faible masse et les planètes géantes : ondes inertielles, structure interne et rotation différentielle : Tidal dissipation in low-mass stars and giant planets : inertial waves, internal structure and differential rotation. [Internet] [Doctoral dissertation]. Université Paris-Saclay (ComUE); 2016. [cited 2021 Jan 27]. Available from: http://www.theses.fr/2016SACLS307.

Council of Science Editors:

Guenel M. Dissipation de marée dans les étoiles de faible masse et les planètes géantes : ondes inertielles, structure interne et rotation différentielle : Tidal dissipation in low-mass stars and giant planets : inertial waves, internal structure and differential rotation. [Doctoral Dissertation]. Université Paris-Saclay (ComUE); 2016. Available from: http://www.theses.fr/2016SACLS307

Western Kentucky University

8. Wang, Xiaojin. The Development of an Integrated Simulation Model on Understandings on the Interaction between Electromagnetic Waves and Nanoparticles.

Degree: MS, Department of Chemistry, 2019, Western Kentucky University

URL: https://digitalcommons.wku.edu/theses/3150

► To investigate the interaction between nanoparticles and electromagnetic waves, a numerical simulation model based on FEM was built in this thesis. Numerical simulation is… (more)

Subjects/Keywords: Nanofluids; Photothermal; Soot; Core-shell nanoparticles; Environmental Chemistry; Materials Chemistry; Optics

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wang, X. (2019). The Development of an Integrated Simulation Model on Understandings on the Interaction between Electromagnetic Waves and Nanoparticles. (Masters Thesis). Western Kentucky University. Retrieved from https://digitalcommons.wku.edu/theses/3150

Chicago Manual of Style (16^th Edition):

Wang, Xiaojin. “The Development of an Integrated Simulation Model on Understandings on the Interaction between Electromagnetic Waves and Nanoparticles.” 2019. Masters Thesis, Western Kentucky University. Accessed January 27, 2021. https://digitalcommons.wku.edu/theses/3150.

MLA Handbook (7^th Edition):

Wang, Xiaojin. “The Development of an Integrated Simulation Model on Understandings on the Interaction between Electromagnetic Waves and Nanoparticles.” 2019. Web. 27 Jan 2021.

Vancouver:

Wang X. The Development of an Integrated Simulation Model on Understandings on the Interaction between Electromagnetic Waves and Nanoparticles. [Internet] [Masters thesis]. Western Kentucky University; 2019. [cited 2021 Jan 27]. Available from: https://digitalcommons.wku.edu/theses/3150.

Council of Science Editors:

Wang X. The Development of an Integrated Simulation Model on Understandings on the Interaction between Electromagnetic Waves and Nanoparticles. [Masters Thesis]. Western Kentucky University; 2019. Available from: https://digitalcommons.wku.edu/theses/3150

University of California – Berkeley

9. Edwards, David Eugene. Elementary Kinetics of Soot Oxidation by OH.

Degree: Mechanical Engineering, 2014, University of California – Berkeley

URL: http://www.escholarship.org/uc/item/7h52r2k4

► The goal of this dissertation is to elucidate detailed pathways, products, and rates leading to soot oxidation by OH. Such information would supplement current soot… (more)

▼ The goal of this dissertation is to elucidate detailed pathways, products, and rates leading to soot oxidation by OH. Such information would supplement current soot modeling which has generally focused more on growth reactions. Indeed, OH oxidation of soot has received no detailed theoretical analysis. The results presented here are a first step to fill this gap in soot modeling.Due to the presumed importance of oxyradical decomposition to soot oxidation, the thermal decomposition of armchair oxyradicals was pursued. A number of different armchair prototype reactions were investigated to determine how rates vary based on oxyradical location and prototype size. Potential energy surfaces were explored and thermal decomposition rates were calculated. The results indicated that armchair edge oxyradicals decompose at rates similar to zigzag edge oxyradicals. These results were used in subsequent OH oxidation study.Next, OH oxidation was studied on a series of prototype soot surfaces to identify which edge sites would lead to rapid oxidation by OH. The potential energy surfaces of three different reactions were explored. The carbon radical site was identified as the most likely candidate for a single OH radical attack leading to CO expulsion. A phenanthrene radical was selected as the prototype structure for this site, and the kinetics of this most promising reaction, OH + phenanthrene radical, were explored. This system, including a number of barrierless reactions, was explored using both chemical-activation and thermal decomposition master-equation simulations. The results confirmed the assumption that oxyradicals are key intermediates; multiple oxyradicals were found, all leading to CO expulsion. The overall rate coefficient of phenanthrene radical oxidation by OH forming CO was found to be insensitive to pressure and temperature and was approximately 1E14 cm3 mol-1 s-1. The OH + phenanthrene radical was also studied on the triplet surface. The rate in this case was found to be about a factor of 6 smaller than the singlet surface results.The two principal processes involved in phenanthrene radical oxidation by OH were H atom migration/elimination followed by oxyradical decomposition. H atom migration/elimination made possible the relatively rapid rearrangement of the PAH edge, forming kinetically favorable oxyradicals which then decomposed. These same two processes are expected to be present in soot surface oxidation by OH. As a preliminary comparison of these theoretical results to soot oxidation experimental results, the collisional efficiency of OH with a phenanthrene radical was calculated and found to be a close match to the experimentally calculated collision efficiency of OH with a soot particle.

Subjects/Keywords: Mechanical engineering; Physical chemistry; Combustion; Graphene; Kinetics; Oxidation; PAH; Soot

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Edwards, D. E. (2014). Elementary Kinetics of Soot Oxidation by OH. (Thesis). University of California – Berkeley. Retrieved from http://www.escholarship.org/uc/item/7h52r2k4

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Edwards, David Eugene. “Elementary Kinetics of Soot Oxidation by OH.” 2014. Thesis, University of California – Berkeley. Accessed January 27, 2021. http://www.escholarship.org/uc/item/7h52r2k4.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Edwards, David Eugene. “Elementary Kinetics of Soot Oxidation by OH.” 2014. Web. 27 Jan 2021.

Vancouver:

Edwards DE. Elementary Kinetics of Soot Oxidation by OH. [Internet] [Thesis]. University of California – Berkeley; 2014. [cited 2021 Jan 27]. Available from: http://www.escholarship.org/uc/item/7h52r2k4.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Edwards DE. Elementary Kinetics of Soot Oxidation by OH. [Thesis]. University of California – Berkeley; 2014. Available from: http://www.escholarship.org/uc/item/7h52r2k4

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Texas A&M University

10. Cruz Quinones, Miguel. Heterogeneous Reaction of NO2 on Soot Surfaces and the Effect of Soot Aging on its Reactivity Leading to HONO Formation.

Degree: MS, Chemistry, 2011, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2009-12-7314

► Soot aerosols are known to be an important atmospheric constituent. The physical and chemical properties of soot allows it to act as a precursor of… (more)

▼ Soot aerosols are known to be an important atmospheric constituent. The physical and chemical properties of soot allows it to act as a precursor of gas-surface heterogeneous reactions, providing active sites for the reduction and oxidation of trace species in the atmosphere, potentially affecting atmospheric composition. In this work the heterogeneous reaction of NO2 on soot leading to nitrous acid (HONO) formation was studied through a series of kinetic uptake experiments and HONO yield measurements. The soot was collected from a diffusion flame using propane and kerosene fuels using two different methods. A low pressure fast-flow reactor coupled to a Chemical Ionization Mass Spectrometer (CIMS) was used to monitor NO2 and HONO signals evolution using atmospheric-level NO2 concentration. HONO yields up to 100 percent were measured and NO2 uptake coefficients varying from 5.6x10-6 to 1.6x10-4 were obtained. Heating soot samples before exposure to NO2 increased HONO yield and the NO2 uptake coefficient on soot due to the removal of the organic fraction from the soot backbone unblocking active sites, which become accessible for the heterogeneous reaction. From the kinetic uptake curves and the effect observed in the HONO yield and NO2 uptake coefficient measurements by heating the soot samples, our results support a complex oxidation-reduction mechanism of reaction. This heterogeneous reaction mechanism involves a combination of competitive adsorptive and reductive centers on soot surface where NO2 is converted into HONO, and the presence of processes on soot where HONO can be decomposed producing other products. Atmospheric soot "aging" effect on the reactivity of soot toward NO2 and HONO yield was studied by coating the soot surface with glutaric acid, succinic acid, sulfuric acid, and pyrene. Glutaric and succinic acid increased both HONO yield and the NO2 uptake coefficients, while sulfuric acid decreased both. However, pyrene did not show any particular trend. Advisors/Committee Members: Zhang, Renyi (advisor), Brooks, Sarah D. (committee member), Lucchese, Robert R. (committee member), North, Simon W. (committee member).

Subjects/Keywords: Atmospheric Chemistry; heterogeneous reaction of NO2 on soot surfaces; HONO formation

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Cruz Quinones, M. (2011). Heterogeneous Reaction of NO2 on Soot Surfaces and the Effect of Soot Aging on its Reactivity Leading to HONO Formation. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2009-12-7314

Chicago Manual of Style (16^th Edition):

Cruz Quinones, Miguel. “Heterogeneous Reaction of NO2 on Soot Surfaces and the Effect of Soot Aging on its Reactivity Leading to HONO Formation.” 2011. Masters Thesis, Texas A&M University. Accessed January 27, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2009-12-7314.

MLA Handbook (7^th Edition):

Cruz Quinones, Miguel. “Heterogeneous Reaction of NO2 on Soot Surfaces and the Effect of Soot Aging on its Reactivity Leading to HONO Formation.” 2011. Web. 27 Jan 2021.

Vancouver:

Cruz Quinones M. Heterogeneous Reaction of NO2 on Soot Surfaces and the Effect of Soot Aging on its Reactivity Leading to HONO Formation. [Internet] [Masters thesis]. Texas A&M University; 2011. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2009-12-7314.

Council of Science Editors:

Cruz Quinones M. Heterogeneous Reaction of NO2 on Soot Surfaces and the Effect of Soot Aging on its Reactivity Leading to HONO Formation. [Masters Thesis]. Texas A&M University; 2011. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2009-12-7314

Arizona State University

11. Hamilton, George A. Soot Black Carbon Dynamics in Arid/urban Ecosystems.

Degree: PhD, Chemistry, 2013, Arizona State University

URL: http://repository.asu.edu/items/20912

► Black carbon (BC) is the product of incomplete combustion of biomass and fossil fuels. It is found ubiquitously in nature and is relevant to studies… (more)

Subjects/Keywords: Chemistry; Biogeochemistry; biodegradation; carbon; isotopes; photo-oxidation; solubility; soot

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hamilton, G. A. (2013). Soot Black Carbon Dynamics in Arid/urban Ecosystems. (Doctoral Dissertation). Arizona State University. Retrieved from http://repository.asu.edu/items/20912

Chicago Manual of Style (16^th Edition):

Hamilton, George A. “Soot Black Carbon Dynamics in Arid/urban Ecosystems.” 2013. Doctoral Dissertation, Arizona State University. Accessed January 27, 2021. http://repository.asu.edu/items/20912.

MLA Handbook (7^th Edition):

Hamilton, George A. “Soot Black Carbon Dynamics in Arid/urban Ecosystems.” 2013. Web. 27 Jan 2021.

Vancouver:

Hamilton GA. Soot Black Carbon Dynamics in Arid/urban Ecosystems. [Internet] [Doctoral dissertation]. Arizona State University; 2013. [cited 2021 Jan 27]. Available from: http://repository.asu.edu/items/20912.

Council of Science Editors:

Hamilton GA. Soot Black Carbon Dynamics in Arid/urban Ecosystems. [Doctoral Dissertation]. Arizona State University; 2013. Available from: http://repository.asu.edu/items/20912

University of Southern California

12. Dames, Enoch Edward. Kinetic modeling of high-temperature oxidation and pyrolysis of one-ringed aromatic and alkane compounds.

Degree: PhD, Mechanical Engineering, 2012, University of Southern California

URL: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/51809/rec/3716

► Future internal combustion engine design will rely on accurate kinetic models of surrogate fuels that mimic their fossil fuel derived counterparts, having hundreds or thousands… (more)

▼ Future internal combustion engine design will rely on accurate kinetic models of surrogate fuels that mimic their fossil fuel derived counterparts, having hundreds or thousands of different chemical species. At the same time, technological advances in alternative fuel production will enable tailor made surrogate fuels for use in pre-existing internal combustion engines. For these reasons, a large collaborative effort has been underway to identify and understand key species and their reaction kinetics. This work focuses on two such compound classes - one-ringed aromatics and alkanes, as they make up a significant portion of almost all transportation fuels. ❧ Attempts at understanding the combustion characteristics of new compounds frequently results in the identification of missing kinetic pathways and/or key intermediate species. For a kineticist, there is never a lack of new and interesting reactions to explore. This thesis work presents mechanisms seeking to explain observed behavior in the three different premixed flame regions: the postflame region, the flame sheet, and the preflame region. ❧ Three topics will be addressed: 1) persistent free radicals in large aromatic compounds, which serve as analogs to systems in nascent and mature soot that may help explain the continued growth of soot in the postflame region where hydrogen radicals are scarce. 2) mutual isomerization through H-atom shifts in benzylic and methylphenyl type radicals for toluene, and o-, m-, and p-xylene isomers. The relative structure of xylene isomers and specifically the number of H atoms immediately adjacent to the methyl groups can have a direct impact on their high-temperature oxidation and appear to explain the observed differences in xylene oxidation behind reflected shock waves and in laminar premixed flames. 3) the isomerization and dissociation of cyclohexyl radicals, which marks a necessary step towards a detailed understanding of dehydrogenation from cyclohexane and methylcyclohexane to benzene and toluene. Focus lies on branching fractions of cyclohexyl isomerization/dissociation for various temperatures and pressures, and its relationship to differing observations on the role of early dehydrogenation in benzene formation for various flame configurations. Advisors/Committee Members: Wang, Hai (Committee Chair), Krylov, Anna I. (Committee Member), Egolfopoulos, Fokion N. (Committee Member).

Subjects/Keywords: combustion; kinetics; reaction rate theory; ab initio; gas-phase chemistry; soot

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Dames, E. E. (2012). Kinetic modeling of high-temperature oxidation and pyrolysis of one-ringed aromatic and alkane compounds. (Doctoral Dissertation). University of Southern California. Retrieved from http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/51809/rec/3716

Chicago Manual of Style (16^th Edition):

Dames, Enoch Edward. “Kinetic modeling of high-temperature oxidation and pyrolysis of one-ringed aromatic and alkane compounds.” 2012. Doctoral Dissertation, University of Southern California. Accessed January 27, 2021. http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/51809/rec/3716.

MLA Handbook (7^th Edition):

Dames, Enoch Edward. “Kinetic modeling of high-temperature oxidation and pyrolysis of one-ringed aromatic and alkane compounds.” 2012. Web. 27 Jan 2021.

Vancouver:

Dames EE. Kinetic modeling of high-temperature oxidation and pyrolysis of one-ringed aromatic and alkane compounds. [Internet] [Doctoral dissertation]. University of Southern California; 2012. [cited 2021 Jan 27]. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/51809/rec/3716.

Council of Science Editors:

Dames EE. Kinetic modeling of high-temperature oxidation and pyrolysis of one-ringed aromatic and alkane compounds. [Doctoral Dissertation]. University of Southern California; 2012. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/51809/rec/3716

University of Manchester

13. Wang, Xinguang. Advanced RANS and Near-Wall Turbulence Modelling for High-Speed Flow.

Degree: 2019, University of Manchester

URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:318489

► This research focuses on the development of wall functions suitable for the prediction of high-speed compressible flows. Wall-functions avoid the need for prohibitively expensive fine… (more)

▼ This research focuses on the development of wall functions suitable for the prediction of high-speed compressible flows. Wall-functions avoid the need for prohibitively expensive fine near-wall meshes and low-Re models of turbulence which still involve a certain amount of approximation. The conventional log-law-based wall functions, however, have limitations in even incompressible cases, which are further compounded when applied to high-speed compressible flows. The objective of this study is to examine the performance of an advanced analytical wall-function treatment which has been successfully used in a range of incompressible flows and explore how compressibility effects could be accounted for in such approaches. The starting point was the implementation of the analytical wall function proposed by Craft et al (2002) in OpenFoam and its subsequent use for the prediction of the impinging shock interaction and compression corner cases up to a Mach number of 3. The wall pressure and skin friction results obtained by the original version result in improvements over those of the standard wall function (log-law based) and are close to those obtained by the low-Re number modelling for supersonic flows. However, an unphysical behaviour is encountered when applying it to higher Mach number cases. A compressible flow version of the analytical wall function is proposed which includes the following modifications: a)inclusion of thermal dissipation terms in the analytical equation for the energy variation over the near-wall cells, b) Variable molecular viscosity (due to temperature variations) over the viscous sub-layer, c) improved variation of the convection terms in the near-wall cell analytical equations. The resultant model has been applied to the above flows up to Mach numbers of 9 and comparisons drawn with experimental data and with predictions from the log-law based wall functions and from the Low-Re Launder and Sharma model. The present results are consistently closer to the data than those of other wall functions in some instances even better than those of the low-Re number. Improvements are especially noticeable in the prediction of the wall heat flux rates, where the log-law wall function generally predicts too low values in the shock interaction region, while the low-Re model, predicts too high heat transfer rates in the highest Mach number cases, as a result of overpredicting turbulence levels where extremely rapid near-wall temperature variations are found. Advisors/Committee Members: CRAFT, TIMOTHY TJ, Iacovides, Hector, Craft, Timothy.

Subjects/Keywords: wall functions; Shock wave/turbulence boundary layer interactions; turbulence modelling; analytical wall function

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wang, X. (2019). Advanced RANS and Near-Wall Turbulence Modelling for High-Speed Flow. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:318489

Chicago Manual of Style (16^th Edition):

Wang, Xinguang. “Advanced RANS and Near-Wall Turbulence Modelling for High-Speed Flow.” 2019. Doctoral Dissertation, University of Manchester. Accessed January 27, 2021. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:318489.

MLA Handbook (7^th Edition):

Wang, Xinguang. “Advanced RANS and Near-Wall Turbulence Modelling for High-Speed Flow.” 2019. Web. 27 Jan 2021.

Vancouver:

Wang X. Advanced RANS and Near-Wall Turbulence Modelling for High-Speed Flow. [Internet] [Doctoral dissertation]. University of Manchester; 2019. [cited 2021 Jan 27]. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:318489.

Council of Science Editors:

Wang X. Advanced RANS and Near-Wall Turbulence Modelling for High-Speed Flow. [Doctoral Dissertation]. University of Manchester; 2019. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:318489

14. Umaima Gazal. Studies of solute solvent interactions; -.

Degree: Chemistry, 2013, Aligarh Muslim University

URL: http://shodhganga.inflibnet.ac.in/handle/10603/12895

►

Densities (and#961;) and speeds of sound (u) have been measured of (L-leucine / L-isoleucine / L-glutamine / L-alanine / glycylglycine + 0.512 mol.kg-1 aqueous K2SO4… (more)

▼

Densities (and#961;) and speeds of sound (u) have been measured of (L-leucine / L-isoleucine / L-glutamine / L-alanine / glycylglycine + 0.512 mol.kg-1 aqueous K2SO4 / KNO3) solutions as a function of molal concentration of amino acid / peptide at different temperatures: (298.15, 303.15, 308.15, 313.15, 318.15 and 323.15) K. The measured density values exhibit usual increasing trend with an increase in molal concentration of solutions and decreasing trend with an increase in temperature for the systems under investigation. Using density data, the apparent molar volumes ( ) and the partial molar volumes ( ) of L-leucine, L-isoleucine, L-glutamine, L-alanine and glycylglycine in 0.512 mol.kg-1 aqueous K2SO4 / KNO3 solutions have been calculated. The observed values of the studied amino acid / peptide in said aqueous electrolyte solutions have been found to be positive and larger in magnitude than those of corresponding values in aqueous medium. The larger values of of L-leucine / L-isoleucine / L-glutamine / L-alanine / glycylglycine in 0.512 mol kg-1 aqueous K2SO4 / in 0.512 mol kg-1 aqueous KNO3 solutions than the corresponding values in aqueous medium have been ascribe to the following interactions occuring in solutions: newline(i) ion-ion interactions between the K+, SO42-, NO3- ions and (COO- , NH3+) newlinezwitterionic end groups (ii) ion-hydrophilic interactions between ions and hydrophilic groups (-CONH2-, CONH) of amino acid / peptide (iii) ion-non polar group interactions occurring between ions and the non-polar groups newline(-CH2 / -CH3) of amino acid / peptide. The trends of variations of values of L-leucine / L-isoleucine / L-glutamine / L-alanine / glycylglycine in 0.512 mol.kg-1 aqueous K2SO4 or 0.512 mol.kg-1 aqueous KNO3 solutions is found to be as: L-leucine gt L-isoleucine gt L-glutamine gt glycylglycine gt L-alanine newlineThe transfer partial molar volumes of L-leucine / L-isoleucine / L-glutamine / L-alanine / glycylglycine from water to 0.512 mol.kg-1 aqueous K2SO4 / KNO3 solutions have been calculated. The and#8710;tr values of L-l

References p.205-215, Appendix p.216-221, Publications and presentations p.222-223

Advisors/Committee Members: Riyazuddeen.

Subjects/Keywords: Chemistry; solute solvent interactions

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Gazal, U. (2013). Studies of solute solvent interactions; -. (Thesis). Aligarh Muslim University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/12895

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Gazal, Umaima. “Studies of solute solvent interactions; -.” 2013. Thesis, Aligarh Muslim University. Accessed January 27, 2021. http://shodhganga.inflibnet.ac.in/handle/10603/12895.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Gazal, Umaima. “Studies of solute solvent interactions; -.” 2013. Web. 27 Jan 2021.

Vancouver:

Gazal U. Studies of solute solvent interactions; -. [Internet] [Thesis]. Aligarh Muslim University; 2013. [cited 2021 Jan 27]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/12895.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Gazal U. Studies of solute solvent interactions; -. [Thesis]. Aligarh Muslim University; 2013. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/12895

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Universidade do Rio Grande do Sul

15. Centeno, Felipe Roman. Modelagem da radiação térmica em chamas turbulentas da combustão de metano em ar.

Degree: 2014, Universidade do Rio Grande do Sul

URL: http://hdl.handle.net/10183/96316

►

Este trabalho analisa numericamente a transferência de calor radiativa em uma chama turbulenta de metano-ar. São resolvidas equações de conservação de massa, quantidade de movimento,… (more)

▼

Este trabalho analisa numericamente a transferência de calor radiativa em uma chama turbulenta de metano-ar. São resolvidas equações de conservação de massa, quantidade de movimento, energia, espécies químicas gasosas e fuligem, e variância da flutuação de temperatura em coordenadas cilíndricas axissimétricas. O modelo de combustão é o Eddy Break-Up – Arrhenius, com reação de combustão em duas etapas. O modelo de turbulência é o k −e padrão. A modelagem das interações turbulência-radiação (TRI - do inglês: Turbulence-Radiation Interactions) considera a “correlação combinada entre coeficiente de absorção e temperatura” e a “autocorrelação de temperatura”. O termo fonte de calor radiativo é calculado com o método de ordenadas discretas, considerando os modelos de gás cinza (GC) e da soma-ponderada-de-gases-cinza (WSGG – do inglês: weighted-sum-of-gray-gases) com correlações clássicas e recentes. O modelo linha-por-linha, considerado benchmark, também é empregado no cálculo daquele termo fonte, porém em cálculos desacoplados entre radiação e dinâmica de fluidos computacional (CFD - do inglês: Computational Fluid Dynamics), com o objetivo de avaliar os modelos WSGG e GC. Primeiramente, estudou-se o efeito da radiação térmica dos gases H2O e CO2 através dos modelos GC e WSGG, em cálculos acoplados radiação-CFD. Os resultados mostraram que os campos de temperatura e do termo fonte de calor radiativo, a transferência de calor para a parede da câmara e a fração radiativa, foram sensíveis aos diferentes modelos, enquanto o efeito sobre as concentrações das espécies foi de menor relevância para o modelo de combustão considerado. Os resultados obtidos com o modelo WSGG mais recente ficaram mais próximos dos dados experimentais da literatura, enquanto que a consideração das interações TRI melhorou esta concordância. As principais contribuições das interações TRI foram sobre a temperatura máxima e a fração radiativa, concordando com resultados da literatura. Os efeitos radiativos da fuligem juntamente com os gases também foram estudados, sendo importantes sobre o termo fonte de calor radiativo somente na região onde a fuligem estava presente (aumento de 30%). O fluxo de calor radiativo sobre a parede radial da câmara aumentou 25% na região de maior concentração de fuligem. A contribuição dos gases para a transferência radiativa foi de 92% e a da fuligem foi de 8%. Ao comparar os resultados dos modelos WSGG e GC com a solução benchmark, considerando o meio composto por gases, o modelo WSGG mais recente foi o que apresentou os melhores resultados (erro máximo 22,49%, médio 4,72%), enquanto ao considerar o meio composto por gases e fuligem, os erros foram menores (máximo 11,07%, médio 2,95%).

This work analyses numerically the thermal radiation heat transfer on a methane-air turbulent non-premixed flame. Conservation equations for mass, momentum, gaseous chemical species and soot, energy, and temperature variance, are solved in axisymmetric coordinates. The combustion model is Eddy Break-Up – Arrhenius, with two steps for the…

Advisors/Committee Members: França, Francis Henrique Ramos.

Subjects/Keywords: Radiation; Aterro sanitário; Spectral models; Lixiviação; Biogás; Turbulence-radiation interactions; Combustion

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Centeno, F. R. (2014). Modelagem da radiação térmica em chamas turbulentas da combustão de metano em ar. (Thesis). Universidade do Rio Grande do Sul. Retrieved from http://hdl.handle.net/10183/96316

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Centeno, Felipe Roman. “Modelagem da radiação térmica em chamas turbulentas da combustão de metano em ar.” 2014. Thesis, Universidade do Rio Grande do Sul. Accessed January 27, 2021. http://hdl.handle.net/10183/96316.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Centeno, Felipe Roman. “Modelagem da radiação térmica em chamas turbulentas da combustão de metano em ar.” 2014. Web. 27 Jan 2021.

Vancouver:

Centeno FR. Modelagem da radiação térmica em chamas turbulentas da combustão de metano em ar. [Internet] [Thesis]. Universidade do Rio Grande do Sul; 2014. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/10183/96316.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Centeno FR. Modelagem da radiação térmica em chamas turbulentas da combustão de metano em ar. [Thesis]. Universidade do Rio Grande do Sul; 2014. Available from: http://hdl.handle.net/10183/96316

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Princeton University

16. Wu, Fujia. Dynamics and Chemistry of Laminar and Turbulent Expanding Flames .

Degree: PhD, 2014, Princeton University

URL: http://arks.princeton.edu/ark:/88435/dsp016t053j22r

► The present work consists of a series of experimental studies on expanding laminar and turbulent flames. The first goal is to use the laminar stable… (more)

Subjects/Keywords: chemistry; combustion; dynamics; energy; fuel; turbulence

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wu, F. (2014). Dynamics and Chemistry of Laminar and Turbulent Expanding Flames . (Doctoral Dissertation). Princeton University. Retrieved from http://arks.princeton.edu/ark:/88435/dsp016t053j22r

Chicago Manual of Style (16^th Edition):

Wu, Fujia. “Dynamics and Chemistry of Laminar and Turbulent Expanding Flames .” 2014. Doctoral Dissertation, Princeton University. Accessed January 27, 2021. http://arks.princeton.edu/ark:/88435/dsp016t053j22r.

MLA Handbook (7^th Edition):

Wu, Fujia. “Dynamics and Chemistry of Laminar and Turbulent Expanding Flames .” 2014. Web. 27 Jan 2021.

Vancouver:

Wu F. Dynamics and Chemistry of Laminar and Turbulent Expanding Flames . [Internet] [Doctoral dissertation]. Princeton University; 2014. [cited 2021 Jan 27]. Available from: http://arks.princeton.edu/ark:/88435/dsp016t053j22r.

Council of Science Editors:

Wu F. Dynamics and Chemistry of Laminar and Turbulent Expanding Flames . [Doctoral Dissertation]. Princeton University; 2014. Available from: http://arks.princeton.edu/ark:/88435/dsp016t053j22r

17. Schnitzler, Elijah G. Studies of Intermolecular Interactions in Atmospheric Aggregates: From Molecular Clusters to Aerosols.

Degree: PhD, Department of Chemistry, 2016, University of Alberta

URL: https://era.library.ualberta.ca/files/cvt150j50t

► Intermolecular interactions dictate the fate and impact of atmospheric oxygenated organic compounds that form from the photo-oxidation of hydrocarbons. Here, intermolecular interactions in aggregates involving… (more)

▼ Intermolecular interactions dictate the fate and impact of atmospheric oxygenated organic compounds that form from the photo-oxidation of hydrocarbons. Here, intermolecular interactions in aggregates involving photo-oxidation products of aromatic precursors are examined using an interdisciplinary approach. Molecular-scale aggregates – in particular, complexes of water and carboxylic acids – were investigated using rotational spectroscopy. The lowest-energy structures of the monohydrates of two aromatic carboxylic acids, benzoic acid and o-toluic acid, were determined experimentally; the water and acid moieties hydrogen bond to give six-membered intermolecular rings. The percentage of each acid hydrated in the gas phase is predicted to be low, but these interactions are important for aromatic acids at the air-water interface of aqueous particles. The two lowest-energy isomers of the oxalic acid–water complex, a probable nucleation precursor, were also observed. In the lowest-energy isomer, water bridges the two acid groups and lowers the barrier to decarboxylation. In the other isomer, water hydrogen bonds to only one group and increases the barrier. For larger dicarboxylic acids, the latter topology is predicted to be the most stable, so water-catalysed enhancement of overtone-induced decarboxylation is plausible for only oxalic acid. The spectra, structures, and internal dynamics of four methyl- and dimethylnaphthalenes, small polycyclic aromatic hydrocarbons present in the atmosphere, were also investigated. Nano-scale aerosols – in particular, internally-mixed particles of black carbon and secondary organic aerosol – were investigated using smog chamber experiments. The morphological evolution of black carbon due to coatings of secondary organic aerosol is the same for a series of four aromatic precursors. The evolution of black carbon is found to be dependent on the coating surface tension; higher surface tensions lead to more compact black carbon particles, as intermolecular interactions between molecules in the coating become stronger. Based on the observed surface tension-dependence, the surface tension of secondary organic aerosol derived from m-xylene was determined, providing an essential constraint on global climate models. Cumulatively, these investigations provide insights into the fate and impact of oxidation products in the gas phase, at the air-water interface, and in the bulk aerosol phase.

Subjects/Keywords: intermolecular interactions; hydrogen-bonded clusters; carboxylic acid hydrates; rotational spectroscopy; secondary organic aerosol; soot aggregates; smog chamber experiments

12 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Schnitzler, E. G. (2016). Studies of Intermolecular Interactions in Atmospheric Aggregates: From Molecular Clusters to Aerosols. (Doctoral Dissertation). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/cvt150j50t

Chicago Manual of Style (16^th Edition):

Schnitzler, Elijah G. “Studies of Intermolecular Interactions in Atmospheric Aggregates: From Molecular Clusters to Aerosols.” 2016. Doctoral Dissertation, University of Alberta. Accessed January 27, 2021. https://era.library.ualberta.ca/files/cvt150j50t.

MLA Handbook (7^th Edition):

Schnitzler, Elijah G. “Studies of Intermolecular Interactions in Atmospheric Aggregates: From Molecular Clusters to Aerosols.” 2016. Web. 27 Jan 2021.

Vancouver:

Schnitzler EG. Studies of Intermolecular Interactions in Atmospheric Aggregates: From Molecular Clusters to Aerosols. [Internet] [Doctoral dissertation]. University of Alberta; 2016. [cited 2021 Jan 27]. Available from: https://era.library.ualberta.ca/files/cvt150j50t.

Council of Science Editors:

Schnitzler EG. Studies of Intermolecular Interactions in Atmospheric Aggregates: From Molecular Clusters to Aerosols. [Doctoral Dissertation]. University of Alberta; 2016. Available from: https://era.library.ualberta.ca/files/cvt150j50t

University of Washington

18. Kalia, Aman Ved. Comparison of Sooting behavior amongst various Liquid Fuels.

Degree: 2015, University of Washington

URL: http://hdl.handle.net/1773/34042

► Hydrocarbon combustion at fuel – air equivalence ratio (φ) greater than 1 results in incomplete combustion and formation of black flaky substance, soot. Soot is… (more)

Subjects/Keywords: aviation fuel; combustion; hydrocarbons; meker burner; premixed laminar; soot; Mechanical engineering; Chemistry; mechanical engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kalia, A. V. (2015). Comparison of Sooting behavior amongst various Liquid Fuels. (Thesis). University of Washington. Retrieved from http://hdl.handle.net/1773/34042

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kalia, Aman Ved. “Comparison of Sooting behavior amongst various Liquid Fuels.” 2015. Thesis, University of Washington. Accessed January 27, 2021. http://hdl.handle.net/1773/34042.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kalia, Aman Ved. “Comparison of Sooting behavior amongst various Liquid Fuels.” 2015. Web. 27 Jan 2021.

Vancouver:

Kalia AV. Comparison of Sooting behavior amongst various Liquid Fuels. [Internet] [Thesis]. University of Washington; 2015. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/1773/34042.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kalia AV. Comparison of Sooting behavior amongst various Liquid Fuels. [Thesis]. University of Washington; 2015. Available from: http://hdl.handle.net/1773/34042

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Georgia

19. Wheeler, Steven Edge. Accurate thermochemistry of key soot formation intermediates.

Degree: 2014, University of Georgia

URL: http://hdl.handle.net/10724/23276

► Precise enthalpies of formation of key soot formation intermediates C3H3, C4H3, and C4H5 have been determined through systematic extrapolations of ab initio energies within the… (more)

Subjects/Keywords: soot formation; combustion; computational chemistry; perturbation theory; ZAPT; spin contamination; thermochemistry; basis set extrapolation

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wheeler, S. E. (2014). Accurate thermochemistry of key soot formation intermediates. (Thesis). University of Georgia. Retrieved from http://hdl.handle.net/10724/23276

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Wheeler, Steven Edge. “Accurate thermochemistry of key soot formation intermediates.” 2014. Thesis, University of Georgia. Accessed January 27, 2021. http://hdl.handle.net/10724/23276.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Wheeler, Steven Edge. “Accurate thermochemistry of key soot formation intermediates.” 2014. Web. 27 Jan 2021.

Vancouver:

Wheeler SE. Accurate thermochemistry of key soot formation intermediates. [Internet] [Thesis]. University of Georgia; 2014. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/10724/23276.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Wheeler SE. Accurate thermochemistry of key soot formation intermediates. [Thesis]. University of Georgia; 2014. Available from: http://hdl.handle.net/10724/23276

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

20. Dasgupta, Debolina. Turbulence-chemistry interactions for lean premixed flames.

Degree: PhD, Aerospace Engineering, 2018, Georgia Tech

URL: http://hdl.handle.net/1853/60746

► Turbulent combustion, particularly premixed combustion has great practical importance due to their extensive industrial usage in gas turbines, internal combustion engines etc. However, the physics… (more)

▼ Turbulent combustion, particularly premixed combustion has great practical importance due to their extensive industrial usage in gas turbines, internal combustion engines etc. However, the physics governing the inherent multi- scale interactions of turbulence, flow-field and chemistry is not yet well established. A complete understanding of each of these interactions and their coupling is essential for the development of models that can aid simulations of realistic engines (using Large Eddy Simulations (LES) or Reynolds averaged Navier-Stokes equations (RANS). Particularly, understanding the flame structure and its stabilization requires an understanding of the turbulence-chemistry interactions. This can manifest itself in many different forms. For example, flame wrinkling gives rise to flame stretch that can modify the local temperature and species concentrations in turn altering the local chemistry. Also, the smaller eddies in a turbulent flow can penetrate into the preheat and reaction zones changing the species’ gradients within the flame. The influence of turbulence on chemistry can be analyzed in two different ways: firstly, a “global” analysis which investigates the direct impact of turbulence on the chemical pathways (a series of elementary reactions involved in the fuel oxidation process) and secondly, a “local” analysis which investigates the influence of turbulence on the chemical flame structure (i.e. species and reaction rate profiles). To understand these influences of turbulence, this work performs Direct Numerical Simulations (DNS) for lean premixed flames involving three fuels: hydrogen, methane and n-dodecane. A “global” analysis using different metrics such as heat release and species consumption/production is performed to quantify the changes in the chemical pathways. This analysis is performed for the metrics averaged over the entire flame and conditioned on local flame features such as fuel consumption, curvature etc. The results are also compared and contrasted with simple laminar flame models such as unstretched flames, stretched flames and perfectly stirred reactors. In general, the laminar models provide a good estimate for the chemical pathways for these key metrics suggesting turbulence does not have a significant impact on the fuel oxidation pathways. However, this is not true for the reaction rate and species profiles across the flame. Conditional means of these quantities are calculated to identify the “local” influence of turbulence on chemistry. These conditional means are also compared with laminar unstretched and stretched flames to identify regions of good agreement and deviation. The laminar calculations are performed using two different transport models; firstly, the mixture-averaged transport wherein every species diffuses into the mixture with its molecular diffusivity and secondly, Le=1 transport wherein the mass diffusivity of every species is equal to the thermal diffusivity of the mixture eliminating effects of preferential and differential diffusion. Le=1 is considered the… Advisors/Committee Members: Lieuwen, Tim (advisor), Oefelein, Joseph (committee member), Menon, Suresh (committee member), Sun, Wenting (committee member), Sievers, Carsten (committee member).

Subjects/Keywords: Premixed flames; Turbulent combustion; Turbulence-chemistry interactions; Combustion modeling; Numerical combustion

…interactions, turbulence-chemistry interactions are the least understood primarily due to the… …physics of turbulence-chemistry interactions and its impact on the reaction rates and the… …closure models for turbulence-chemistry interactions which can be used for LES and RANS. xxvi… …discussed in detail in the next section. 2 1.2 Turbulence-Chemistry interactions The effect of… …ignition times and blow-off behavior. Even though experimentally studying turbulence-chemistry…

10 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Dasgupta, D. (2018). Turbulence-chemistry interactions for lean premixed flames. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/60746

Chicago Manual of Style (16^th Edition):

Dasgupta, Debolina. “Turbulence-chemistry interactions for lean premixed flames.” 2018. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021. http://hdl.handle.net/1853/60746.

MLA Handbook (7^th Edition):

Dasgupta, Debolina. “Turbulence-chemistry interactions for lean premixed flames.” 2018. Web. 27 Jan 2021.

Vancouver:

Dasgupta D. Turbulence-chemistry interactions for lean premixed flames. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/1853/60746.

Council of Science Editors:

Dasgupta D. Turbulence-chemistry interactions for lean premixed flames. [Doctoral Dissertation]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/60746

University of Michigan

21. He, Haiping. Hydrodynamics of thin plates.

Degree: PhD, Ocean engineering, 2003, University of Michigan

URL: http://hdl.handle.net/2027.42/123399

► Offshore structures such as Spar Platforms and Tension Leg Platforms may experience resonant oscillations in heave under first and more likely second-order wave forces; thus… (more)

▼ Offshore structures such as Spar Platforms and Tension Leg Platforms may experience resonant oscillations in heave under first and more likely second-order wave forces; thus damping becomes a critical factor in limiting the response amplitude of the structures. Usually, these offshore structures are lightly damped; hence, drag-augmenting devices may be required to limit the response amplitude to a safe range. In the present research, thin plates are studied as one method to enhance the hydrodynamic damping of offshore structures. The problem is investigated from both the hydrodynamic force and underlying flow physics viewpoints through force measurement and qualitative/quantitative flow visualization experiments. The force measurements show geometric dependence by examining thickness-to-diameter ratio, reinforcing structure, and edge radius. Additionally, parametric dependence such as oscillation amplitude and frequency are included. The flow physics includes a comparison of the Keulegan-Carpenter number and thickness-to-diameter ratio dependence through a series of flow visualization and Digital Particle Image Velocimetry experiments. It is found that damping coefficients behave differently in three ranges of KC number. The transitional KC number is thickness-to-diameter ratio dependent, and the transition occurs at larger KC number for the thicker disk. The plate thickness-to-diameter ratio affects damping coefficients dramatically at small KC numbers (0 to 1.1). The flow around a 1/87.5 plate experiences four distinct vortex formation modes as the KC number increases from 0 to 1.1. A quantitative analysis of the vortex formation mode at large KC (unidirectional shedding) is conducted. A new turbulent decomposition method is applied to calculate Reynolds stresses; it is concluded that the cycle-to-cycle variation, due to vortex instability and azimuthal structures resulting from vortex-vortex interaction and turbulence-vortex interaction, is not negligible. Advisors/Committee Members: Troesch, Armin (advisor), Perlin, Marc (advisor).

Subjects/Keywords: Hydrodynamics; Thin Plates; Turbulence-vortex Interactions; Vortex-vortex Interactions

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

He, H. (2003). Hydrodynamics of thin plates. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/123399

Chicago Manual of Style (16^th Edition):

He, Haiping. “Hydrodynamics of thin plates.” 2003. Doctoral Dissertation, University of Michigan. Accessed January 27, 2021. http://hdl.handle.net/2027.42/123399.

MLA Handbook (7^th Edition):

He, Haiping. “Hydrodynamics of thin plates.” 2003. Web. 27 Jan 2021.

Vancouver:

He H. Hydrodynamics of thin plates. [Internet] [Doctoral dissertation]. University of Michigan; 2003. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/2027.42/123399.

Council of Science Editors:

He H. Hydrodynamics of thin plates. [Doctoral Dissertation]. University of Michigan; 2003. Available from: http://hdl.handle.net/2027.42/123399

INP Toulouse

22. Wang, Guiquan. Modulation of wall-bounded turbulent flows by large particles : effect of concentration, inertia, and shape : Modification des écoulements turbulents avec paroi, par les particules de taille finie : effet de leur concentration, forme et inertie.

Degree: Docteur es, Dynamique des fluides, 2017, INP Toulouse

URL: http://www.theses.fr/2017INPT0079

► L’effet des inclusions sur la turbulence de l’écoulement est un élément clé à comprendre afin de maîtriser le transport de milieux dispersés, dans le domaine… (more)

▼ L’effet des inclusions sur la turbulence de l’écoulement est un élément clé à comprendre afin de maîtriser le transport de milieux dispersés, dans le domaine du génie pétrolier, environnemental, agroalimentaire, génie de la réaction chimique ou transformation du solide. Les expériences de Matas et al. (PRL, 2003) ont mis en évidence un effet non monotone des particules isodenses (de densité égale à celle du fluide) sur la transition laminaire-turbulent, cet effet dépendant de la taille des particules et de leur concentration dans la suspension. Une petite quantité de particules de taille finie s’est avérée suffisante pour diminuer considérablement le seuil de transition laminaire turbulent. Nous avons utilisé des simulations numériques, basées sur une approche de type “Force Coupling Method” afin de comprendre cet effet. Les domaines de simulations étaient choisis pour accommoder le minimum de structures cohérentes suffisantes pour entretenir la turbulence. Nous avons particulièrement étudié la corrélation entre le comportement instationnaire de l’écoulement et la distribution instantanée de particules, en fonction de la configuration de l’écoulement (Couette plan ou écoulement en canal), de la forme des particules ainsi que leur inertie et concentration. Dans un écoulement de Couette plan turbulent, la contrainte pariétale est augmentée en présence des particules. Les profiles (dans la direction normale aux parois) de vitesse moyenne et des contraintes de Reynolds ne sont pas significativement modifiés en présence des particules, si la viscosité du fluide est remplacée par la viscosité effective de la suspension dans le calcul du nombre de Reynolds de l’écoulement. Par contre l’analyse temporelle et modale des fluctuations de l’écoulement suggère que les particules modifient légèrement le cycle de régénération de la turbulence, à travers l’augmentation d’énergie à petites échelles. En effet, la forme des streaks et le caractère intermittent de l’écoulement sont impactés par la présence des particules, surtout quand elles sont inertielles (de densité supérieure à celle du fluide). Ces résultats ont été publiés dans le journal Physical Review F (Wang et al., 2017). En outre, nous avons montré qu’à fraction volumique égale, les propriétés d’écoulement turbulent des suspensions de particules sphéroïdales de rapport de taille compris entre 0.5 et 2, sont similaires à celles des suspensions de particules sphériques. Le transfert de particules entre les différentes structures cohérentes de l’écoulement est analysé à la fin de la thèse. Néanmoins dans un écoulement en canal, les particules iso denses augmentent l’intensité des contraintes de Reynolds dans le plan transverse. Nous montrons que par leur concentration préférentielle dans les structures cohérentes à côté des parois (les éjections), elles influencent significativement le cycle de régénération en agissant sur tous les processus à la fois linéaires et non linéaires du cycle: la formation des streaks, puis leur rupture et la régénération des vortex alignés avec… Advisors/Committee Members: Climent, Éric (thesis director), Abbas, Micheline (thesis director).

Subjects/Keywords: Ecoulement de suspension; Interactions hydrodynamiques; Particules non sphériques; Turbulence; Simulations numériques; Force Coupling Method; Suspension flow; Hydrodynamic Interactions; Non-spherical particles; Turbulence; Numerical simulation; Force Coupling Method

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wang, G. (2017). Modulation of wall-bounded turbulent flows by large particles : effect of concentration, inertia, and shape : Modification des écoulements turbulents avec paroi, par les particules de taille finie : effet de leur concentration, forme et inertie. (Doctoral Dissertation). INP Toulouse. Retrieved from http://www.theses.fr/2017INPT0079

Chicago Manual of Style (16^th Edition):

Wang, Guiquan. “Modulation of wall-bounded turbulent flows by large particles : effect of concentration, inertia, and shape : Modification des écoulements turbulents avec paroi, par les particules de taille finie : effet de leur concentration, forme et inertie.” 2017. Doctoral Dissertation, INP Toulouse. Accessed January 27, 2021. http://www.theses.fr/2017INPT0079.

MLA Handbook (7^th Edition):

Wang, Guiquan. “Modulation of wall-bounded turbulent flows by large particles : effect of concentration, inertia, and shape : Modification des écoulements turbulents avec paroi, par les particules de taille finie : effet de leur concentration, forme et inertie.” 2017. Web. 27 Jan 2021.

Vancouver:

Wang G. Modulation of wall-bounded turbulent flows by large particles : effect of concentration, inertia, and shape : Modification des écoulements turbulents avec paroi, par les particules de taille finie : effet de leur concentration, forme et inertie. [Internet] [Doctoral dissertation]. INP Toulouse; 2017. [cited 2021 Jan 27]. Available from: http://www.theses.fr/2017INPT0079.

Council of Science Editors:

Wang G. Modulation of wall-bounded turbulent flows by large particles : effect of concentration, inertia, and shape : Modification des écoulements turbulents avec paroi, par les particules de taille finie : effet de leur concentration, forme et inertie. [Doctoral Dissertation]. INP Toulouse; 2017. Available from: http://www.theses.fr/2017INPT0079

23. Gougeon, Pierre. Interactions aérodynamiques entre une turbine haute pression et le premier distributeur basse pression : Investigation of the aerodynamic interactions between a high pressure turbine and the first low pressure vane.

Degree: Docteur es, Mécanique, 2014, Ecully, Ecole centrale de Lyon

URL: http://www.theses.fr/2014ECDL0026

► L’amélioration des performances des turboréacteurs actuels est un enjeu crucial dans un contexte de contraintes économiques et environnementales fortes. Au sein du turboréacteur, le canal… (more)

▼ L’amélioration des performances des turboréacteurs actuels est un enjeu crucial dans un contexte de contraintes économiques et environnementales fortes. Au sein du turboréacteur, le canal inter-turbines, localisé à l’interface entre la turbine Haute Pression (HP) et le premier distributeur Basse Pression (BP), est le siège d’écoulements très complexes. Ainsi, les structures aérodynamiques issues de la turbine HP (sillages, tourbillons et ondes de choc) interagissent fortement entre elles et impactent l’écoulement du distributeur BP, engendrant ainsi des pertes de rendement de l’ensemble de la configuration. Ce travail de thèse s’attache à étudier les phénomènes d’interactions aérodynamiques entre une turbine HP et le premier distributeur BP et à analyser les mécanismes à l’origine des pertes aérodynamiques dans le distributeur BP. Une campagne expérimentale antérieure, réalisée sur un banc d’essai comprenant une turbine HP couplée à un distributeur BP, avait permis de recueillir des mesures de l’écoulement dans des plans situés dans le canal inter-turbines et à l’aval du distributeur BP. En lien avec ces résultats expérimentaux, les simulations numériques menées dans cette étude avec le logiciel elsA s’attachent à restituer précisément la nature tridimensionnelle, instationnaire et turbulente de l’écoulement au sein de cette même configuration. Ces travaux se développent alors en trois étapes principales. Dans un premier temps, une étude stationnaire avec traitement plan de mélange permet de comprendre et quantifier les aspects généraux de l’écoulement. Une évaluation de l’effet de la modélisation turbulente RANS (Reynolds-Averaged Navier-Stokes) et du schéma numérique spatial sur les structures aérodynamiques présentes dans la configuration est réalisée. Dans un deuxième temps, une modélisation turbulente avancée de type ZDES (Zonal Detached-Eddy Simulation) est employée pour la résolution de l’écoulement dans le distributeur BP. Les structures aérodynamiques instationnaires issues de la roue HP amont sont modélisées par une condition limite à l’entrée du domaine de calcul. L’approche ZDES est comparée à une approche Unsteady RANS (URANS) sur la même configuration. La formation et la dissipation des sillages et des tourbillons est significativement différente entre les deux modélisations, ce qui impacte de manière importante la génération des pertes aérodynamiques. Enfin, des simulations URANS de plusieurs configurations permettent de mieux comprendre les effets d’interaction entre les différentes rangées d’aubes. Ainsi, les approches instationnaires chorochroniques prenant en compte un seul rotor et un seul stator évaluent des effets instationnaires importants dans le canal inter-turbines. Ces approches conduisent à la mise en oeuvre d’un calcul sur une configuration multipassages-chorochronique prenant en compte les deux stators et le rotor afin de modéliser complètement les interactions déterministes existantes. Afin de quantifier celles-ci avec précision, une décomposition modale du champ instationnaire est mise… Advisors/Committee Members: Leboeuf, Francis (thesis director), Ngo-Boum, Ghislaine (thesis director), Ferrand, Pascal (thesis director).

Subjects/Keywords: Turbines; Turbomachines; Aérodynamique; Écoulements instationnaires; Interactions rotorstator; Turbulence; Simulation numérique; RANS; DES; Turbine; Turbomachinery; Aerodynamic; Unsteady flows; Rotor-stator interactions; Turbulence; Numerical simulation; RANS; DES

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Gougeon, P. (2014). Interactions aérodynamiques entre une turbine haute pression et le premier distributeur basse pression : Investigation of the aerodynamic interactions between a high pressure turbine and the first low pressure vane. (Doctoral Dissertation). Ecully, Ecole centrale de Lyon. Retrieved from http://www.theses.fr/2014ECDL0026

Chicago Manual of Style (16^th Edition):

Gougeon, Pierre. “Interactions aérodynamiques entre une turbine haute pression et le premier distributeur basse pression : Investigation of the aerodynamic interactions between a high pressure turbine and the first low pressure vane.” 2014. Doctoral Dissertation, Ecully, Ecole centrale de Lyon. Accessed January 27, 2021. http://www.theses.fr/2014ECDL0026.

MLA Handbook (7^th Edition):

Gougeon, Pierre. “Interactions aérodynamiques entre une turbine haute pression et le premier distributeur basse pression : Investigation of the aerodynamic interactions between a high pressure turbine and the first low pressure vane.” 2014. Web. 27 Jan 2021.

Vancouver:

Gougeon P. Interactions aérodynamiques entre une turbine haute pression et le premier distributeur basse pression : Investigation of the aerodynamic interactions between a high pressure turbine and the first low pressure vane. [Internet] [Doctoral dissertation]. Ecully, Ecole centrale de Lyon; 2014. [cited 2021 Jan 27]. Available from: http://www.theses.fr/2014ECDL0026.

Council of Science Editors:

Gougeon P. Interactions aérodynamiques entre une turbine haute pression et le premier distributeur basse pression : Investigation of the aerodynamic interactions between a high pressure turbine and the first low pressure vane. [Doctoral Dissertation]. Ecully, Ecole centrale de Lyon; 2014. Available from: http://www.theses.fr/2014ECDL0026

Universidade do Rio Grande do Sul

24. Santos, Elizaldo Domingues dos. Análise numérica de escoamentos turbulentos não reativos com transferência de calor por convecção e radiação térmica em meios participantes.

Degree: 2011, Universidade do Rio Grande do Sul

URL: http://hdl.handle.net/10183/34750

►

O presente trabalho apresenta um estudo numérico sobre escoamentos turbulentos combinando os mecanismos de transferência de calor por convecção e radiação térmica em meios participantes.… (more)

▼

O presente trabalho apresenta um estudo numérico sobre escoamentos turbulentos combinando os mecanismos de transferência de calor por convecção e radiação térmica em meios participantes. Os principais propósitos são obter um melhor entendimento a respeito da relevância das interações Turbulência-Radiação (TRI) em escoamentos turbulentos não reativos, bem como, investigar o efeito da radiação térmica sobre o comportamento transiente, médio e estatístico dos campos térmicos. Para investigar a relevância das interações TRI em escoamentos turbulentos internos, realiza-se uma comparação entre os fluxos temporais médios por convecção e radiação térmica obtidos através da simulação de grandes escalas (LES) e da modelagem clássica da turbulência (RANS) para escoamentos no regime permanente com as seguintes espessuras ópticas: τ0 = 0.01, 0.10, 1.0, 10.0 e 100.0, que representam desde meios opticamente muito finos até meios muito espessos. Para todos os casos, o número de Reynolds baseado na velocidade de fricção e o número de Prandtl são mantidos fixos: Reτ = 180 e Pr = 0.71. A abordagem da turbulência é realizada a partir dos modelos submalha dinâmico de Smagorinsky (DSSGS) e k – ε padrão no âmbito de LES e RANS, enquanto nenhum modelo de turbulência é utilizado para a equação da transferência radiante (RTE). Com o intuito de contornar as dificuldades relacionadas com a dependência espectral da radiação térmica, todos os meios participantes são tratados como gás cinza. Para a solução numérica das equações de conservação de massa, quantidade de movimento e energia emprega-se um código comercial (FLUENT®) baseado no método de volumes finitos (FVM). A equação da transferência radiante é resolvida pelo método de ordenadas discretas (DOM). A relevância das interações TRI também é investigada em um escoamento não reativo em cavidade cilíndrica com ReD = 22000, Pr = 0.71 e τ0 = 0.10. Além destes casos, é simulado um escoamento transiente em cavidade retangular com ReH = 10000, Pr = 0.71 e τ0 = 10 para avaliar o efeito da radiação térmica sobre o campo térmico transiente. Os resultados mostram que as interações TRI podem ser desprezadas para escoamentos não reativos para meios com espessura óptica menor ou igual a τ0 = 1.0, concordando com resultados da literatura. No entanto, para meios mais espessos as interações TRI passam a ser relevantes, ao contrário do que tem sido afirmado na literatura.

The present work presents a numerical study about turbulent flows with combined convection and thermal radiation heat transfer in participating media. The main purposes of this study are to obtain a better understanding of the relevance of Turbulence-Radiation Interactions (TRI) for non-reactive turbulent flows, as well as, the investigation of the effect of thermal radiation over the time-averaged and statistics of the thermal field for these flows. To investigate the relevance of TRI for turbulent internal flows, it is performed a comparison between the timeaveraged convective and radiative surface fluxes obtained by means of Large…

Advisors/Committee Members: França, Francis Henrique Ramos.

Subjects/Keywords: Transferencia de calor; Turbulence-radiation interactions; Escoamento turbulento; LES; Análise numérica; RANS; Participating media

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Santos, E. D. d. (2011). Análise numérica de escoamentos turbulentos não reativos com transferência de calor por convecção e radiação térmica em meios participantes. (Thesis). Universidade do Rio Grande do Sul. Retrieved from http://hdl.handle.net/10183/34750

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Santos, Elizaldo Domingues dos. “Análise numérica de escoamentos turbulentos não reativos com transferência de calor por convecção e radiação térmica em meios participantes.” 2011. Thesis, Universidade do Rio Grande do Sul. Accessed January 27, 2021. http://hdl.handle.net/10183/34750.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Santos, Elizaldo Domingues dos. “Análise numérica de escoamentos turbulentos não reativos com transferência de calor por convecção e radiação térmica em meios participantes.” 2011. Web. 27 Jan 2021.

Vancouver:

Santos EDd. Análise numérica de escoamentos turbulentos não reativos com transferência de calor por convecção e radiação térmica em meios participantes. [Internet] [Thesis]. Universidade do Rio Grande do Sul; 2011. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/10183/34750.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Santos EDd. Análise numérica de escoamentos turbulentos não reativos com transferência de calor por convecção e radiação térmica em meios participantes. [Thesis]. Universidade do Rio Grande do Sul; 2011. Available from: http://hdl.handle.net/10183/34750

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

25. Mullan, Brendan Lawrence. Under Pressure: Star Clusters in the Tidal Debris of Interacting Galaxies.

Degree: 2013, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/18256

► Pairwise galaxy interactions and mergers are commonly observed phenomena. The complex gravitational potential of interacting galaxies drastically affects their morphologies, producing long tidal tails and… (more)

▼ Pairwise galaxy interactions and mergers are commonly observed phenomena. The complex gravitational potential of interacting galaxies drastically affects their morphologies, producing long tidal tails and other galactic debris. Encounters between galaxies can also be agents of photometric evolution across these tidally disturbed features, prompting bursts of star and star cluster formation over the ~Gyr interaction timescale involved. At extragalactic distances, we rely on luminous star clusters (M_V < -8.5; ~10⁴ – 10⁶ M_sun) to trace the underlying stellar populations and star formation history of the typically dispersed, faint tidal debris. But decades of individual case studies have revealed that tidal tails do not appear to consistently have star clusters, unlike in the disks of gas-rich mergers. The question is why – what is it about tidal tails that allows star cluster formation in some debris fields but not others? Is there some interplay of merging parameters, e.g., tail age, surface brightnesses, colors, gas densities, and progenitor mass ratios, that produce conditions conducive for these bound structures? Do the answers lie in the local densities and kinematics of the tail ISM? To address these questions, I have searched for compact stellar structures within over 20 tidal tails in different pairs of interacting galaxies using the Wide Field Planetary Camera 2 (WFPC2) on the Hubble Space Telescope (HST). My collection of homogeneously observed tidal tails spans a parameter space of interaction characteristics that could allow luminous star clusters to form and survive. I first characterized and quantified the populations of star clusters within these tails and compared them to various global properties of the interactions that produced them. I also constructed indirect methods to compare the cluster populations and their imprinted formation characteristics with those seen in other extragalactic environments. Using archival data from ATCA, WHISP, and the Very Large Array, I additionally analyzed the turbulent warm neutral medium, the dominant component of the tail ISM, of most of the tidal tail regions within the sample. I examined the roles of ~kpc-scale HI densities, pressures, and kinematics in establishing the conditions required for star cluster formation on smaller (~pc) scales, and how these quantities empirically vary by the global tail properties I studied. In synthesizing these results, a rudimentary paradigm is now emerging, where the formation of luminous clusters in tidal tails depends largely on the turbulent character and amount of hydrogen gas in their local environment. These conditions are determined in part by how the galaxies interact and the ingredients they bring to the cosmic table. Advisors/Committee Members: Jane Camilla Charlton, Dissertation Advisor/Co-Advisor, Jane Camilla Charlton, Committee Chair/Co-Chair, Yuexing Cindy Li, Committee Chair/Co-Chair, Caryl Ann Gronwall, Committee Member, Eric D Feigelson, Committee Member, Douglas Cowen, Committee Member.

Subjects/Keywords: Astronomy; tidal tails; radio astronomy; star clusters; galaxy interactions; star formation; ISM; turbulence; photometry

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Mullan, B. L. (2013). Under Pressure: Star Clusters in the Tidal Debris of Interacting Galaxies. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/18256

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Mullan, Brendan Lawrence. “Under Pressure: Star Clusters in the Tidal Debris of Interacting Galaxies.” 2013. Thesis, Penn State University. Accessed January 27, 2021. https://submit-etda.libraries.psu.edu/catalog/18256.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Mullan, Brendan Lawrence. “Under Pressure: Star Clusters in the Tidal Debris of Interacting Galaxies.” 2013. Web. 27 Jan 2021.

Vancouver:

Mullan BL. Under Pressure: Star Clusters in the Tidal Debris of Interacting Galaxies. [Internet] [Thesis]. Penn State University; 2013. [cited 2021 Jan 27]. Available from: https://submit-etda.libraries.psu.edu/catalog/18256.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Mullan BL. Under Pressure: Star Clusters in the Tidal Debris of Interacting Galaxies. [Thesis]. Penn State University; 2013. Available from: https://submit-etda.libraries.psu.edu/catalog/18256

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

York University

26. Jiang, Kaiti. Mixing and Deposition in a Jack Pine Forest Canopy.

Degree: MSc -MS, Earth & Space Science, 2019, York University

URL: http://hdl.handle.net/10315/35916

► To study how aerosols mix and deposit to forests, a tower was erected in a jack pine forest as part of the York Athabasca Jack… (more)

Subjects/Keywords: Environmental science; aerosols; aerosol deposition; oil sands; canopy interactions; turbulence; turbulent mixing; jack pine; forest

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Jiang, K. (2019). Mixing and Deposition in a Jack Pine Forest Canopy. (Masters Thesis). York University. Retrieved from http://hdl.handle.net/10315/35916

Chicago Manual of Style (16^th Edition):

Jiang, Kaiti. “Mixing and Deposition in a Jack Pine Forest Canopy.” 2019. Masters Thesis, York University. Accessed January 27, 2021. http://hdl.handle.net/10315/35916.

MLA Handbook (7^th Edition):

Jiang, Kaiti. “Mixing and Deposition in a Jack Pine Forest Canopy.” 2019. Web. 27 Jan 2021.

Vancouver:

Jiang K. Mixing and Deposition in a Jack Pine Forest Canopy. [Internet] [Masters thesis]. York University; 2019. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/10315/35916.

Council of Science Editors:

Jiang K. Mixing and Deposition in a Jack Pine Forest Canopy. [Masters Thesis]. York University; 2019. Available from: http://hdl.handle.net/10315/35916

Colorado State University

27. Grant, Leah Danielle. Cold pool processes in different environments.

Degree: PhD, Atmospheric Science, 2018, Colorado State University

URL: http://hdl.handle.net/10217/189266

► Cold pools are localized regions of dense air near Earth's surface. They form in association with precipitating clouds in many environments ranging from moist tropical… (more)

▼ Cold pools are localized regions of dense air near Earth's surface. They form in association with precipitating clouds in many environments ranging from moist tropical to semi-arid continental conditions, and they play important roles in weather in climate. The overarching goal of this dissertation research is to improve our process-level understanding of cold pool interactions with different components of the Earth system, focusing on two key knowledge gaps: (1) interactions with Earth's surface in continental environments; and (2) interactions with organized convective systems in tropical oceanic environments. The primary goal of the first study conducted in this dissertation is to evaluate how surface sensible heat fluxes impact cold pool dissipation in dry continental environments via two pathways: (a) by directly heating the cold pool, and (b) by changing mixing rates between cold pool air and environmental air through altering turbulence intensity. Idealized 2D simulations of isolated cold pools are conducted with varying sensible heat flux formulations to determine the relative importance of these two mechanisms. The results demonstrate that the impact of sensible heat fluxes on mixing, i.e. mechanism (b), contributes most significantly to cold pool dissipation. Cold pool – land surface interactions in semi-arid continental conditions are investigated in the second study. Two questions are addressed: (1) how does the land surface respond to the cold pool; and (2) to what extent do land surface feedbacks modulate the cold pool evolution? Idealized 3D simulations of a cold pool evolving in a turbulent boundary layer are conducted to answer these questions. The land surface cools in response to the cold pool, resulting in suppressed sensible heat fluxes in the center of the cold pool. However, sensible heat fluxes are enhanced near the edge of the cold pool in association with higher wind speeds, leading to cold pool dissipation from the edge inwards. The land surface interactions are shown to strongly affect the cold pool, reducing its lifetime, size, and intensity by up to 50%. Preliminary analysis of a cold pool that was observed in northeastern Colorado on 17 May 2017 ("The Bees Day") during the C3LOUD-Ex field campaign is presented in the third study. The observed case exhibits similar environmental and cold pool characteristics to the first two numerical studies, thereby providing observational context for their hypotheses and conclusions. The objective of the fourth study presented in this dissertation is to determine the role of cold pools in organized tropical oceanic convective systems. To address this goal, two convective systems embedded in a weakly sheared cloud population approaching radiative-convective equilibrium are simulated at high resolution. The cold pools are weakened in the sensitivity tests by suppressing evaporation rates below cloud base. Both of the convective systems respond in a consistent manner as follows: (a) when cold pools are weakened, the convective intensity increases; and… Advisors/Committee Members: van den Heever, Susan C. (advisor), Randall, David A. (committee member), Rutledge, Steven A. (committee member), Niemann, Jeffrey D. (committee member).

Subjects/Keywords: convective processes; surface fluxes; turbulence; land - atmosphere interactions; cold pools; tropical convective systems

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Grant, L. D. (2018). Cold pool processes in different environments. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/189266

Chicago Manual of Style (16^th Edition):

Grant, Leah Danielle. “Cold pool processes in different environments.” 2018. Doctoral Dissertation, Colorado State University. Accessed January 27, 2021. http://hdl.handle.net/10217/189266.

MLA Handbook (7^th Edition):

Grant, Leah Danielle. “Cold pool processes in different environments.” 2018. Web. 27 Jan 2021.

Vancouver:

Grant LD. Cold pool processes in different environments. [Internet] [Doctoral dissertation]. Colorado State University; 2018. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/10217/189266.

Council of Science Editors:

Grant LD. Cold pool processes in different environments. [Doctoral Dissertation]. Colorado State University; 2018. Available from: http://hdl.handle.net/10217/189266

28. Brody, Sarah. Physical Drivers of the Spring Phytoplankton Bloom in the Subpolar North Atlantic Ocean .

Degree: 2015, Duke University

URL: http://hdl.handle.net/10161/9850

► The timing of the spring phytoplankton bloom in the subpolar North Atlantic Ocean has important consequences for the marine carbon cycle and ecosystems. There… (more)

▼ The timing of the spring phytoplankton bloom in the subpolar North Atlantic Ocean has important consequences for the marine carbon cycle and ecosystems. There are currently several proposed mechanisms to explain the timing of this bloom. The conventional theory holds that the bloom begins when the ocean warms and the seasonal mixed layer shoals in the spring, decreasing the depth to which phytoplankton are mixed and increasing the light available to the population. Recent work has attributed the beginning of the bloom to decreases in turbulence within the upper ocean, driven by the onset of positive heat fluxes or decreases in the strength of local winds. Other studies have focused on the increase in the seasonal mixed layer in the winter as a driver of changes in ecosystem interactions and a control on the spring bloom. Finally, submesoscale eddies, occurring as a result of lateral density gradients, have been proposed as a stratification mechanism that can create phytoplankton blooms prior to the onset of ocean surface warming. This dissertation critically examines and compares the proposed theories for the initiation of the spring bloom and draws on these theories to propose a new framework: that blooms begin when the active mixing depth shoals, a process generally driven by a weakening of surface heat fluxes and consequent shift from convective mixing to wind-driven mixing. Using surface forcing data, we develop a parameterization for the active mixing depth from estimates of the largest energy-containing eddies in the upper ocean. Using in situ records of turbulent mixing and biomass, we find that the spring phytoplankton bloom occurs after mixing shifts from being driven by convection to being driven by wind, and that biomass increases as the active mixing depth shoals. Using remote sensing data, we examine patterns of bloom initiation in the North Atlantic at the basin scale, compare current theories of bloom initiation, and find that the shoaling of the active mixing depth better predicts the onset of the bloom across the North Atlantic subpolar basin and over multiple years than do other current theories. Additionally, using a process study model, we evaluate the importance of submesoscale eddy-driven stratification as a control on the initiation of the spring bloom, determining that this mechanism has a relatively minor effect on alleviation of phytoplankton light limitation. Finally, we describe potential techniques and tools to examine whether interannual variability in the active mixing depth acts as a control on variability in the timing of the spring bloom. Advisors/Committee Members: Lozier, M. Susan (advisor).

Subjects/Keywords: Physical oceanography; Biological oceanography; marine ecosystems; ocean mixing; physical-biological interactions; Phytoplankton; turbulence

11 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Brody, S. (2015). Physical Drivers of the Spring Phytoplankton Bloom in the Subpolar North Atlantic Ocean . (Thesis). Duke University. Retrieved from http://hdl.handle.net/10161/9850

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Brody, Sarah. “Physical Drivers of the Spring Phytoplankton Bloom in the Subpolar North Atlantic Ocean .” 2015. Thesis, Duke University. Accessed January 27, 2021. http://hdl.handle.net/10161/9850.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Brody, Sarah. “Physical Drivers of the Spring Phytoplankton Bloom in the Subpolar North Atlantic Ocean .” 2015. Web. 27 Jan 2021.

Vancouver:

Brody S. Physical Drivers of the Spring Phytoplankton Bloom in the Subpolar North Atlantic Ocean . [Internet] [Thesis]. Duke University; 2015. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/10161/9850.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Brody S. Physical Drivers of the Spring Phytoplankton Bloom in the Subpolar North Atlantic Ocean . [Thesis]. Duke University; 2015. Available from: http://hdl.handle.net/10161/9850

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Duke University

29. Ghannam, Khaled. The Effects of Land Surface Heating and Roughness Elements on the Structure and Scaling Laws of Atmospheric Boundary Layer Turbulence .

Degree: 2017, Duke University

URL: http://hdl.handle.net/10161/16269

► The atmospheric boundary-layer is the lowest 500-2000 m of the Earth's atmosphere where much of human life and ecosystem services reside. This layer responds… (more)

▼ The atmospheric boundary-layer is the lowest 500-2000 m of the Earth's atmosphere where much of human life and ecosystem services reside. This layer responds to land surface (e.g. buoyancy and roughness elements) and slowly evolving free tropospheric (e.g. temperature and humidity lapse rates) conditions that arguably mediate and modulate biosphere-atmosphere interactions. Such response often results in spatially- and temporally-rich turbulence scales that continue to be the subject of inquiry given their significance to a plethora of applications in environmental sciences and engineering. The work here addresses key aspects of boundary layer turbulence with a focus on the role of roughness elements (vegetation canopies) and buoyancy (surface heating) in modifying the well-studied picture of shear-dominated wall-bounded turbulence. A combination of laboratory channel experiments, field experiments, and numerical simulations are used to explore three distinct aspects of boundary layer turbulence. These are: \begin{itemize} \item The concept of ergodicity in turbulence statistics within canopies: It has been long-recognized that homogeneous and stationary turbulence is ergodic, but less is known about the effects of inhomogeneity introduced by the presence of canopies on the turbulence statistics. A high resolution (temporal and spatial) flume experiment is used here to test the convergence of the time statistics of turbulent scalar concentrations to their ensemble (spatio-temporal) counterpart. The findings indicate that within-canopy scalar statistics have a tendency to be ergodic, mostly in shallow layers (close to canopy top) where the sweeping flow events appear to randomize the statistics. Deeper layers within the canopy are dominated by low-dimensional (quasi-deterministic) von K{\'a}rm{\'a}n vortices that tend to break ergodicity. \item Scaling laws of turbulent velocity spectra and structure functions in near-surface atmospheric turbulence: the existence of a logarithmic scaling in the structure function of the longitudinal and vertical velocity components is examined using five experimental data sets that span the roughness sub-layer above vegetation canopies, the atmospheric surface-layer above a lake and a grass field, and an open channel experiment. The results indicate that close to the wall/surface, this scaling exists in the longitudinal velocity structure function only, with the vertical velocity counterpart exhibiting a much narrower extent of this range due to smaller separation of scales. Phenomenological aspects of the large-scale eddies show that the length scale formed by the friction velocity and energy dissipation acts as a dominant similarity length scale in collapsing experimental data at different heights, mainly due to the imbalance between local production and dissipation of turbulence kinetic energy. \item Nonlocal heat transport in the convective atmospheric boundary-layer: Failure of the mean gradient-diffusion (K-theory) in the convective boundary-layer is… Advisors/Committee Members: Katul, Gabriel G (advisor).

Subjects/Keywords: Atmospheric sciences; Environmental engineering; Hydrologic sciences; Atmospheric turbulence; Ecology; Land-Atmosphere interactions; Surface Hydrology

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ghannam, K. (2017). The Effects of Land Surface Heating and Roughness Elements on the Structure and Scaling Laws of Atmospheric Boundary Layer Turbulence . (Thesis). Duke University. Retrieved from http://hdl.handle.net/10161/16269

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Ghannam, Khaled. “The Effects of Land Surface Heating and Roughness Elements on the Structure and Scaling Laws of Atmospheric Boundary Layer Turbulence .” 2017. Thesis, Duke University. Accessed January 27, 2021. http://hdl.handle.net/10161/16269.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Ghannam, Khaled. “The Effects of Land Surface Heating and Roughness Elements on the Structure and Scaling Laws of Atmospheric Boundary Layer Turbulence .” 2017. Web. 27 Jan 2021.

Vancouver:

Ghannam K. The Effects of Land Surface Heating and Roughness Elements on the Structure and Scaling Laws of Atmospheric Boundary Layer Turbulence . [Internet] [Thesis]. Duke University; 2017. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/10161/16269.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Ghannam K. The Effects of Land Surface Heating and Roughness Elements on the Structure and Scaling Laws of Atmospheric Boundary Layer Turbulence . [Thesis]. Duke University; 2017. Available from: http://hdl.handle.net/10161/16269

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

30. Dehnavi, Mahmood. A numerical investigation of microgravity ethylene/oxygen/nitrogen spherical diffusion flames at their soot free limit.

Degree: 2016, University of Hawaii – Manoa

URL: http://hdl.handle.net/10125/100951

►

M.S. University of Hawaii at Manoa 2012.

Soot, which is a byproduct of incomplete combustion from hydrocarbon/air flames, is a major cause of premature deaths… (more)

Subjects/Keywords: soot

…Different components of the main code 29 4.1. Soot formation process 36 4.2. Transition from… …sooty to soot-free condition for 4 different flames with the same fuel concentration and… …applied to reduce the formation of soot, and lead to improved performance of combustion devices… …hydrocarbons (PAHs), which are soot precursors. Among these pollutants, soot is responsible… …per year are caused by inhalation of soot particles in USA alone. In New Jersey, for…

11 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Dehnavi, M. (2016). A numerical investigation of microgravity ethylene/oxygen/nitrogen spherical diffusion flames at their soot free limit. (Thesis). University of Hawaii – Manoa. Retrieved from http://hdl.handle.net/10125/100951

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Dehnavi, Mahmood. “A numerical investigation of microgravity ethylene/oxygen/nitrogen spherical diffusion flames at their soot free limit.” 2016. Thesis, University of Hawaii – Manoa. Accessed January 27, 2021. http://hdl.handle.net/10125/100951.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Dehnavi, Mahmood. “A numerical investigation of microgravity ethylene/oxygen/nitrogen spherical diffusion flames at their soot free limit.” 2016. Web. 27 Jan 2021.

Vancouver:

Dehnavi M. A numerical investigation of microgravity ethylene/oxygen/nitrogen spherical diffusion flames at their soot free limit. [Internet] [Thesis]. University of Hawaii – Manoa; 2016. [cited 2021 Jan 27]. Available from: http://hdl.handle.net/10125/100951.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Dehnavi M. A numerical investigation of microgravity ethylene/oxygen/nitrogen spherical diffusion flames at their soot free limit. [Thesis]. University of Hawaii – Manoa; 2016. Available from: http://hdl.handle.net/10125/100951

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

		in
And / Or
		in
And / Or
		in
And / Or
		in

Open Access Theses and Dissertations