subject:(Particle method)

Penn State University

1. Chen, Wei. Numerical Studies of Seismically Induced Slope Deformation Using Smoothed Particle Hydrodynamics Method.

Degree: 2012, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/16010

► There has been growing interest in improving current procedures for estimating seismically-induced deformations of natural and man-made slopes due to recently frequent earthquake events and… (more)

▼ There has been growing interest in improving current procedures for estimating seismically-induced deformations of natural and man-made slopes due to recently frequent earthquake events and the resulted damaged to infrastructure systems. The aim of this study is to develop a numerical model to effectively and reliably assess seismically-induced slope deformations that typically involve large deformations and complex soil constitutive behaviors. A numerical model based on the meshfree Smoothed Particle Hydrodynamics (SPH) method has been developed by implementing various advanced constitutive models into the SPH formulations. The developed model is validated by two readily available and well-documented experiments: axisymmetric collapses of granular columns and model slope tests on a shaking table. For the former, the non-dilatant Drucker-Prager (D-P) constitutive relationship with perfect plasticity is used. The developed model precisely reproduces the experimentally-observed three regimes of flow patterns based on the initial aspect ratio of the granular column. In addition to the flow patterns, the simulated final deposit height and run-out distance along with the non-deformed region after the collapse of granular columns are in excellent agreement with experimental data in the literature. For the latter, a constitutive model that combines the strain-softening viscoplasticity and Modified Kondner and Zelasko (MKZ) rule is implemented and utilized to account for the effects of wave propagation in the sliding mass, cyclic nonlinear behavior of soil, and progressive reduction in shear strength during sliding, which are not explicitly considered in various Newmark-type analyses widely used in the current research and practice in geotechnical earthquake engineering. The initiation of slope failure and subsequent progressive development of the sliding surface are successfully captured by the developed SPH model. A localized shear band along the failure surface and a bulge near the toe of the model slope are observed in the simulations, showing a good agreement with the experimental observations. The simulated failure mode, displacement time histories, and acceleration response spectra at several monitor locations along the model slope also agree well with the experimental recordings. Based on the validated SPH model, a parametric study is followed to investigate the effects of spatial parameters including both particle spacing and smooth length on the accuracy of SPH simulations. The parametric study also investigates the effects of material strength and shear modulus along with boundary conditions on the seismically-induced slope deformations, providing insights into the mechanisms of earthquake-induced slope deformations. It is thus suggested that the proposed SPH model is an effective tool for assessing the seismic performance of soil slopes. It may be also used to advance the computational capability of modeling geotechnical engineering phenomena involving large deformations. Advisors/Committee Members: Tong Qiu, Dissertation Advisor/Co-Advisor, Tong Qiu, Committee Chair/Co-Chair, Daniel G Linzell, Committee Member, Prasenjit Basu, Committee Member, Shelley Marie Stoffels, Committee Member, Derek Elsworth, Committee Member.

Subjects/Keywords: Smoothed Particle Hydrodynamics Method; Large Deformation; Dynam

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APA (6^th Edition):

Chen, W. (2012). Numerical Studies of Seismically Induced Slope Deformation Using Smoothed Particle Hydrodynamics Method. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/16010

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):

Chen, Wei. “Numerical Studies of Seismically Induced Slope Deformation Using Smoothed Particle Hydrodynamics Method.” 2012. Thesis, Penn State University. Accessed March 06, 2021. https://submit-etda.libraries.psu.edu/catalog/16010.

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

MLA Handbook (7^th Edition):

Chen, Wei. “Numerical Studies of Seismically Induced Slope Deformation Using Smoothed Particle Hydrodynamics Method.” 2012. Web. 06 Mar 2021.

Vancouver:

Chen W. Numerical Studies of Seismically Induced Slope Deformation Using Smoothed Particle Hydrodynamics Method. [Internet] [Thesis]. Penn State University; 2012. [cited 2021 Mar 06]. Available from: https://submit-etda.libraries.psu.edu/catalog/16010.

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

Council of Science Editors:

Chen W. Numerical Studies of Seismically Induced Slope Deformation Using Smoothed Particle Hydrodynamics Method. [Thesis]. Penn State University; 2012. Available from: https://submit-etda.libraries.psu.edu/catalog/16010

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

University of New South Wales

2. Wang, Xing. Particle dynamics of granular flow in a model shear cell.

Degree: Materials Science & Engineering, 2012, University of New South Wales

URL: http://handle.unsw.edu.au/1959.4/52332 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:11005/SOURCE1?view=true

► The successful design and control of the handling processes of granular materials depend on the accurate measurement of the flow properties. One of the typical… (more)

▼ The successful design and control of the handling processes of granular materials depend on the accurate measurement of the flow properties. One of the typical shear testers, which are classical apparatus widely used to measure the flow properties of particulate materials, is the annular shear cell. Despite the previous work on annular shear cells, there is still a lack of fundamental understanding of their applications. In this thesis, granular flow dynamics in a model shear cell under conditions relevant to those in an annular shear cell is investigated numerically based on the results obtained by means of the discrete element method (DEM). In this DEM model, the granular material in the cell is regarded as a discrete system, described by Newton’s laws of motion applied on particle scale. This method has been recognized as an effective tool in understanding the fundamentals of particle systems. First, this work establishes the spatial and statistical distributions of microdynamic variables such as velocity, porosity, coordination number and contact force and examines the dependence of these variables on some key physical and operational parameters of particles and the cell. The results derived are shown to be useful in developing a better understanding of granular flow in shear cells from a microscopic perspective. Facilitated by a weighted time-volume averaging method, the microscopic results are then employed to evaluate the macroscopic quantities such as the stress tensor. With the macroscopic quantities, the effectiveness of annular shear cells as a method of measuring particle flow properties is confirmed and the rheology of granular flow in the cell is extracted and analysed in detail. Finally, it is shown that granular flow in the model shear cell can be classified into three regimes: quasi-static, intermediate and inertial, based on the correlations between elastically/kinetically scaled stresses and volume fraction under different scaled stiffness. The flow regime demarcation method employed in this thesis is compared to other methods in literature and investigated in detail with regard to the evolution of internal structures under different flow conditions, with an aim of understanding the underlying physics of different flow regimes and transitions. Some key material properties are also shown to have an obvious influence on the regime transitions. Advisors/Committee Members: Yu, Aibing, Materials Science & Engineering, Faculty of Science, UNSW.

Subjects/Keywords: Particle Dynamics; Discrete Element Method; Shear Cell

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APA (6^th Edition):

Wang, X. (2012). Particle dynamics of granular flow in a model shear cell. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/52332 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:11005/SOURCE1?view=true

Chicago Manual of Style (16^th Edition):

Wang, Xing. “Particle dynamics of granular flow in a model shear cell.” 2012. Doctoral Dissertation, University of New South Wales. Accessed March 06, 2021. http://handle.unsw.edu.au/1959.4/52332 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:11005/SOURCE1?view=true.

MLA Handbook (7^th Edition):

Wang, Xing. “Particle dynamics of granular flow in a model shear cell.” 2012. Web. 06 Mar 2021.

Vancouver:

Wang X. Particle dynamics of granular flow in a model shear cell. [Internet] [Doctoral dissertation]. University of New South Wales; 2012. [cited 2021 Mar 06]. Available from: http://handle.unsw.edu.au/1959.4/52332 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:11005/SOURCE1?view=true.

Council of Science Editors:

Wang X. Particle dynamics of granular flow in a model shear cell. [Doctoral Dissertation]. University of New South Wales; 2012. Available from: http://handle.unsw.edu.au/1959.4/52332 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:11005/SOURCE1?view=true

University of New South Wales

3. Yang, Siyuan Eric. Simulation study of packing of fine particles under electric fields.

Degree: Materials Science & Engineering, 2015, University of New South Wales

URL: http://handle.unsw.edu.au/1959.4/54197 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:13400/SOURCE02?view=true

► Electrostatic precipitation processes have been widely applied to remove particulate matter from flue gases in coal-fired power stations. A high negative voltage is usually applied… (more)

▼ Electrostatic precipitation processes have been widely applied to remove particulate matter from flue gases in coal-fired power stations. A high negative voltage is usually applied to a discharge electrode so that the gases are ionised in such processes. When the suspended particles in flue gases enter the ionised space, they are electrically charged and deposited on collection walls to form a layer of particle packing. Essentially, the underlying working principle of electrostatic precipitation processes is the packing of fine particles under electric fields. Despite the possibility of achieving high collection efficiencies of the precipitation processes through careful tuning of the electrical and aerodynamic conditions, improvements on the removal of fine particulate matter, such as PM2.5 have not been achieved. Understanding the formation process of particle packing under electric fields is the key to improve the collection efficiency of fine particulate matter. Yet, it is mostly impossible to carry out a study on packings of fine particles through practical experiments.In this thesis, we have developed a numerical model based on the discrete element method to simulate packings of fine particles under various electric fields. Both the formed packings under uniform and non-uniform electric fields are comprehensively examined. For the packings under uniform electric fields, the packing structures are characterised in terms of the packing fraction, coordination number, radial distribution function, and Voronoi tessellations. Our results indicate that the particle diameter and electric field are the two important parameters that determine the structure of the formed packings under electric fields. Such observations can be explained by the competition between the electric-field-induced electrostatic interactions and the interparticle van der Waals interactions during the formation of stable packings. For the packings under non-uniform electric fields, special emphasis is given to the elliptical-shaped packing structural profiles commonly observed in electrostatic precipitation processes. The results have demonstrated that non-uniform packing structures are formed as a result of the imposed non-uniform electric fields. Despite the non-uniformity of the overall structural profile, the local packing structures are correlated to the local electric fields in terms of packing fraction and coordination number. These findings may lead to better controls of the formed packings under various electric fields.In addition, a novel numerical method to evaluate electrical transport in the formed packings under electric fields is presented. Both the electrical potential and electric current on each and every particle in a packing are numerically solved to obtain the effective electrical conductivity of the packing. Here, the focus is given to the contacts between particles. Our results have shown that the three variables, the material properties of particles, the contact area between particles and packing structures all have… Advisors/Committee Members: Yu, Aibing, Materials Science & Engineering, Faculty of Science, UNSW, Dong, Kejun, Materials Science & Engineering, Faculty of Science, UNSW, Zou, Ruiping, Materials Science & Engineering, Faculty of Science, UNSW.

Subjects/Keywords: Particle packing; Discrete element method; Electrostatic precipitation

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APA (6^th Edition):

Yang, S. E. (2015). Simulation study of packing of fine particles under electric fields. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/54197 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:13400/SOURCE02?view=true

Chicago Manual of Style (16^th Edition):

Yang, Siyuan Eric. “Simulation study of packing of fine particles under electric fields.” 2015. Doctoral Dissertation, University of New South Wales. Accessed March 06, 2021. http://handle.unsw.edu.au/1959.4/54197 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:13400/SOURCE02?view=true.

MLA Handbook (7^th Edition):

Yang, Siyuan Eric. “Simulation study of packing of fine particles under electric fields.” 2015. Web. 06 Mar 2021.

Vancouver:

Yang SE. Simulation study of packing of fine particles under electric fields. [Internet] [Doctoral dissertation]. University of New South Wales; 2015. [cited 2021 Mar 06]. Available from: http://handle.unsw.edu.au/1959.4/54197 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:13400/SOURCE02?view=true.

Council of Science Editors:

Yang SE. Simulation study of packing of fine particles under electric fields. [Doctoral Dissertation]. University of New South Wales; 2015. Available from: http://handle.unsw.edu.au/1959.4/54197 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:13400/SOURCE02?view=true

NSYSU

4. Lee, Kuan-Wei. Effects of staggered fiber arrangement on aerosol particle transport and deposition in obstructed laminar flows using lattice Boltzmann method.

Degree: Master, Mechanical and Electro-Mechanical Engineering, 2014, NSYSU

URL: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-1026114-184704

► The aim of this paper is to present a 2-D computational model of particle-laden flows over staggered fibers at a Reynolds number of 1 by… (more)

Subjects/Keywords: Particle loading; Lattice Boltzmann cell automation method; Particle capture efficiency; Lattice Boltzmann Method; Staggered fibers

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APA (6^th Edition):

Lee, K. (2014). Effects of staggered fiber arrangement on aerosol particle transport and deposition in obstructed laminar flows using lattice Boltzmann method. (Thesis). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-1026114-184704

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):

Lee, Kuan-Wei. “Effects of staggered fiber arrangement on aerosol particle transport and deposition in obstructed laminar flows using lattice Boltzmann method.” 2014. Thesis, NSYSU. Accessed March 06, 2021. http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-1026114-184704.

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

MLA Handbook (7^th Edition):

Lee, Kuan-Wei. “Effects of staggered fiber arrangement on aerosol particle transport and deposition in obstructed laminar flows using lattice Boltzmann method.” 2014. Web. 06 Mar 2021.

Vancouver:

Lee K. Effects of staggered fiber arrangement on aerosol particle transport and deposition in obstructed laminar flows using lattice Boltzmann method. [Internet] [Thesis]. NSYSU; 2014. [cited 2021 Mar 06]. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-1026114-184704.

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

Council of Science Editors:

Lee K. Effects of staggered fiber arrangement on aerosol particle transport and deposition in obstructed laminar flows using lattice Boltzmann method. [Thesis]. NSYSU; 2014. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-1026114-184704

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

Texas A&M University

5. Ivanova, Nina. Improved Synthetic Methods for Patchy Particles.

Degree: MS, Mechanical Engineering, 2012, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10211

► Patchy particles are patterned particles with at least one well-defined patch that can have highly directional and strongly anisotropic interactions with other particles or surfaces.… (more)

Subjects/Keywords: Janus particle; patchy particle; colloidal; synthetic method; capillary condensation

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APA (6^th Edition):

Ivanova, N. (2012). Improved Synthetic Methods for Patchy Particles. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10211

Chicago Manual of Style (16^th Edition):

Ivanova, Nina. “Improved Synthetic Methods for Patchy Particles.” 2012. Masters Thesis, Texas A&M University. Accessed March 06, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10211.

MLA Handbook (7^th Edition):

Ivanova, Nina. “Improved Synthetic Methods for Patchy Particles.” 2012. Web. 06 Mar 2021.

Vancouver:

Ivanova N. Improved Synthetic Methods for Patchy Particles. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10211.

Council of Science Editors:

Ivanova N. Improved Synthetic Methods for Patchy Particles. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10211

Delft University of Technology

6. Seetharaman, Venkatesan (author). Implementation of a vortex particle scheme to analyze the wake of a wind turbine modeled using actuator lines.

Degree: 2019, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:4c06f73c-a6d6-4a9f-9c4d-ad32a4944785

►

The efficiency of a wind turbine depends largely on the wake of the upstream turbine. Seeking to contribute towards the development of a wind farm… (more)

Subjects/Keywords: Wind turbine; Vortex Particle Method; Fast Multipole Method

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APA (6^th Edition):

Seetharaman, V. (. (2019). Implementation of a vortex particle scheme to analyze the wake of a wind turbine modeled using actuator lines. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:4c06f73c-a6d6-4a9f-9c4d-ad32a4944785

Chicago Manual of Style (16^th Edition):

Seetharaman, Venkatesan (author). “Implementation of a vortex particle scheme to analyze the wake of a wind turbine modeled using actuator lines.” 2019. Masters Thesis, Delft University of Technology. Accessed March 06, 2021. http://resolver.tudelft.nl/uuid:4c06f73c-a6d6-4a9f-9c4d-ad32a4944785.

MLA Handbook (7^th Edition):

Seetharaman, Venkatesan (author). “Implementation of a vortex particle scheme to analyze the wake of a wind turbine modeled using actuator lines.” 2019. Web. 06 Mar 2021.

Vancouver:

Seetharaman V(. Implementation of a vortex particle scheme to analyze the wake of a wind turbine modeled using actuator lines. [Internet] [Masters thesis]. Delft University of Technology; 2019. [cited 2021 Mar 06]. Available from: http://resolver.tudelft.nl/uuid:4c06f73c-a6d6-4a9f-9c4d-ad32a4944785.

Council of Science Editors:

Seetharaman V(. Implementation of a vortex particle scheme to analyze the wake of a wind turbine modeled using actuator lines. [Masters Thesis]. Delft University of Technology; 2019. Available from: http://resolver.tudelft.nl/uuid:4c06f73c-a6d6-4a9f-9c4d-ad32a4944785

University of Sydney

7. Moon, Jiyoung. Rheological Behavior of Complex Fluid with Deformable and Rigid Particles .

Degree: 2017, University of Sydney

URL: http://hdl.handle.net/2123/17106

► Predicting the rheological properties of particles in matrix is one of the most challenging and complicated problems in material and fluid sciences. The complication is… (more)

Subjects/Keywords: Rheology; Lattice Boltzmann method; Immersed boundary method; Suspension; Rough particle; Microfluidics

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APA (6^th Edition):

Moon, J. (2017). Rheological Behavior of Complex Fluid with Deformable and Rigid Particles . (Thesis). University of Sydney. Retrieved from http://hdl.handle.net/2123/17106

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):

Moon, Jiyoung. “Rheological Behavior of Complex Fluid with Deformable and Rigid Particles .” 2017. Thesis, University of Sydney. Accessed March 06, 2021. http://hdl.handle.net/2123/17106.

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

MLA Handbook (7^th Edition):

Moon, Jiyoung. “Rheological Behavior of Complex Fluid with Deformable and Rigid Particles .” 2017. Web. 06 Mar 2021.

Vancouver:

Moon J. Rheological Behavior of Complex Fluid with Deformable and Rigid Particles . [Internet] [Thesis]. University of Sydney; 2017. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/2123/17106.

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

Council of Science Editors:

Moon J. Rheological Behavior of Complex Fluid with Deformable and Rigid Particles . [Thesis]. University of Sydney; 2017. Available from: http://hdl.handle.net/2123/17106

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

Loughborough University

8. Young, Michael I. Synthesis of zinc oxide nanoparticles with different morphologies by wet chemistry routes.

Degree: PhD, 2016, Loughborough University

URL: http://hdl.handle.net/2134/25368

► The objectives of this project were to synthesise semi-conducting ceramic nanoparticles including zinc oxide (ZnO) and aluminium doped zinc oxide (AZO) through a wet chemistry… (more)

Subjects/Keywords: 669; ZnO; AZO; Nanoparticles; Synthesis; Particle size; Particle morphology; Wet chemistry; Co-precipitation method; Hydrothermal method; Orthogonal method; Characterisation

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

APA (6^th Edition):

Young, M. I. (2016). Synthesis of zinc oxide nanoparticles with different morphologies by wet chemistry routes. (Doctoral Dissertation). Loughborough University. Retrieved from http://hdl.handle.net/2134/25368

Chicago Manual of Style (16^th Edition):

Young, Michael I. “Synthesis of zinc oxide nanoparticles with different morphologies by wet chemistry routes.” 2016. Doctoral Dissertation, Loughborough University. Accessed March 06, 2021. http://hdl.handle.net/2134/25368.

MLA Handbook (7^th Edition):

Young, Michael I. “Synthesis of zinc oxide nanoparticles with different morphologies by wet chemistry routes.” 2016. Web. 06 Mar 2021.

Vancouver:

Young MI. Synthesis of zinc oxide nanoparticles with different morphologies by wet chemistry routes. [Internet] [Doctoral dissertation]. Loughborough University; 2016. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/2134/25368.

Council of Science Editors:

Young MI. Synthesis of zinc oxide nanoparticles with different morphologies by wet chemistry routes. [Doctoral Dissertation]. Loughborough University; 2016. Available from: http://hdl.handle.net/2134/25368

Penn State University

9. Kumar, Rakesh. Development of a Kinetic Particle-based Method to Model the Multi-scale Physics of Expanding Flows .

Degree: 2011, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/11591

► Multi-scale transitional flows through a nozzle into vacuum are widely studied flows because of their numerous applications in many fields of science and engineering, and,… (more)

▼ Multi-scale transitional flows through a nozzle into vacuum are widely studied flows because of their numerous applications in many fields of science and engineering, and, especially in aerospace sciences. These flows are usually characterized by multiple flow length scales, which significantly complicate their accurate and numerically efficient modeling. Experimental studies under such conditions are rare and expensive. For both micro and meso-sized nozzles operating in the space near-vacuum environment, the interaction of flows with sensitive spacecraft surfaces at high altitudes is important, because back-flows produced by such devices can cause contamination to sensitive electronic devices such as optical instruments and solar panels. This damage can potentially jeopardize the active lifetime of expensive space missions. The development of accurate numerical tools capable of simulating multi-scale transitional flows is therefore important, but at the same time, challenging, because the flow regime changes from continuum to transitional along the length of the domain. The continuum techniques based on the solution of the Navier-Stokes equations encounter physical challenges when applied to these flows. In such a scenario, the study of high speed rarefied flows, involving strong thermo-chemical non-equilibrium, suggests direct consideration of the Boltzmann equation. The Direct Simulation Monte-Carlo (DSMC) approach provides a good approximation to the solution of the Boltzmann equation, but the method becomes prohibitively expensive for modeling high density flows. The Bhatnagar-Gross-Krook (BGK) method, which solves a simplified form of the Boltzmann equation, is more effective approach in such situations. A computational framework based on a statistical formulation of the BGK method was therefore developed in this work that can handle polyatomic multi-species gas flows. A number of classic fluid flow problems in semi-rarefied flow regime were studied to ascertain the accuracy of the statistical BGK computational framework, such as supersonic flow over a flat plate, planar Couette flow and expanding gas flows in transitional flow regime. These types of flows are commonly found in microfluidic applications. The statistical BGK and a related approach, the Ellipsoidal-Statistical BGK (ESBGK), were found to be equally accurate but more efficient as compared to the benchmark DSMC method for near-equilibrium gas flows, however, for gas flows far from equilibrium, the DSMC method was found to be the preferred approach. The complimentary features of the statistical (particle) BGK and DSMC methods naturally motivated the development of a new particle-particle hybrid scheme that combines the statistical BGK and DSMC methods for an accurate and numerically efficient modeling of multi-scale flows. The new particle-particle hybrid scheme eliminated the typical numerical issues associated with the continuum-particle hybrid schemes, such as issues related to the imposition of boundary conditions at the interfaces. The key idea… Advisors/Committee Members: Prof Deborah A Levin, Dissertation Advisor/Co-Advisor, Deborah A Levin, Committee Chair/Co-Chair, Philip John Morris, Committee Member, Barbara Jane Garrison, Committee Member, Adrianus C Van Duin, Committee Member.

Subjects/Keywords: molecular dynamics; DSMC-ESBGK hybrid method; Particle-particle hybrid scheme; homogeneous condensation modeling

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APA (6^th Edition):

Kumar, R. (2011). Development of a Kinetic Particle-based Method to Model the Multi-scale Physics of Expanding Flows . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/11591

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):

Kumar, Rakesh. “Development of a Kinetic Particle-based Method to Model the Multi-scale Physics of Expanding Flows .” 2011. Thesis, Penn State University. Accessed March 06, 2021. https://submit-etda.libraries.psu.edu/catalog/11591.

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

MLA Handbook (7^th Edition):

Kumar, Rakesh. “Development of a Kinetic Particle-based Method to Model the Multi-scale Physics of Expanding Flows .” 2011. Web. 06 Mar 2021.

Vancouver:

Kumar R. Development of a Kinetic Particle-based Method to Model the Multi-scale Physics of Expanding Flows . [Internet] [Thesis]. Penn State University; 2011. [cited 2021 Mar 06]. Available from: https://submit-etda.libraries.psu.edu/catalog/11591.

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

Council of Science Editors:

Kumar R. Development of a Kinetic Particle-based Method to Model the Multi-scale Physics of Expanding Flows . [Thesis]. Penn State University; 2011. Available from: https://submit-etda.libraries.psu.edu/catalog/11591

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

University of Oklahoma

10. Vo, Minh. Computational investigation of non-covalent stabilization of nanoparticle suspensions and their propagation in porous media.

Degree: PhD, 2016, University of Oklahoma

URL: http://hdl.handle.net/11244/46950

► In this study, Dissipative Particle Dynamics (DPD) and Lagrangian Particle Tracking (LPT) methods were used to investigate computationally the non-covalent stabilization of carbon nanotubes (CNT)… (more)

▼ In this study, Dissipative Particle Dynamics (DPD) and Lagrangian Particle Tracking (LPT) methods were used to investigate computationally the non-covalent stabilization of carbon nanotubes (CNT) in water by using polymers and surfactants as well as the propagation of stabilized nanoparticles (NPs) in porous media. First of all, the interaction parameters of CNT and water in DPD was validated by comparing with results from Molecular Dynamics (MD) simulations in case of the water flow past an array of single-walled carbon nanotubes (SWCNT) in different Reynolds number flows. For polymer stabilization, it was presented the conformation of PVP molecules on carbon nanoparticle (CNP) surface. Depending on the surface area and shape of NPs, there were three configurations of polymer molecules when attached on CNP surface including trains, loops and tails. The physical adsorption of PVP on CNP depended on the shear rate of the flow. There were three possible states of NPs coated with polymer under the shear. They consisted of adsorbed, shear-affected and separated states. The range of shear rate for each state was determined for CNPs with different shapes (sphere, cylinder and graphene-like). For surfactant stabilization, CNT surface changed from hydrophobic to hydrophilic in the presence of the surfactants alfoterra 123-8s (AF) and tergitol 15-s-40 (TG) surfactant adsorption. This leads to increase the solubility of CNT in water. In our simulation, it was found that AF and TG surfactant primarily formed both hemi-micelles and random adsorption on CNT surface. The assembly of surfactants on CNT relied on the interaction of the surfactant tail and the CNT surface. For surfactants in solution, most micelles had spherical shape. In the binary surfactant system, the presence of TG on the CNT surface provided a considerable hydrophilic steric effect, due to the ethylene oxide (EO) groups of TG molecules. It was also seen that the adsorption of AF was more favorable than TG on the CNT surface. Our results are applicable, in a qualitative sense, to the more general case of adsorption of surfactants on the hydrophobic surface of cylindrically-shaped nanoscale objects. Moreover, we found that sodium dodecyl sulfate (SDS) surfactant can adsorb inside surface of SWCNT if diameter of SWCNT is larger than 3 nm. When SDS was adsorbed in the hollow part of the SWCNT, the behavior of water inside the nanotube was found to be significantly changed. In addition, SDS molecules increased the retention of water beads inside SWCNT (diameter ≥ 3nm), while water diffusivity was decreased. Depending on the concentration of surfactant, SDS inside SWCNT can accumulate from 1% to 13% of the total of adsorbed surfactant. Besides, the steric effect of adsorbed PVP molecules in CNT coated PVP particle was evaluated by calculating the interaction force between particle – particle and particle – surface. The computations indicated that the repulsion of PVP polymer reduced the agglomeration of CNTs in solution and their deposition on silica surface.… Advisors/Committee Members: Papavassiliou, Dimitrios (advisor), Harwell, Jeffrey (committee member), Resasco, Daniel (committee member), Shambaugh, Robert (committee member), Shiau, Benjamin (Bor-Jier) (committee member).

Subjects/Keywords: Engineering, Chemical.; Dissipative Particle Dynamics simulation; Carbon nanotubes; Surfactants; Polymers; Lagrangian Particle tracking method

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

APA (6^th Edition):

Vo, M. (2016). Computational investigation of non-covalent stabilization of nanoparticle suspensions and their propagation in porous media. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/46950

Chicago Manual of Style (16^th Edition):

Vo, Minh. “Computational investigation of non-covalent stabilization of nanoparticle suspensions and their propagation in porous media.” 2016. Doctoral Dissertation, University of Oklahoma. Accessed March 06, 2021. http://hdl.handle.net/11244/46950.

MLA Handbook (7^th Edition):

Vo, Minh. “Computational investigation of non-covalent stabilization of nanoparticle suspensions and their propagation in porous media.” 2016. Web. 06 Mar 2021.

Vancouver:

Vo M. Computational investigation of non-covalent stabilization of nanoparticle suspensions and their propagation in porous media. [Internet] [Doctoral dissertation]. University of Oklahoma; 2016. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/11244/46950.

Council of Science Editors:

Vo M. Computational investigation of non-covalent stabilization of nanoparticle suspensions and their propagation in porous media. [Doctoral Dissertation]. University of Oklahoma; 2016. Available from: http://hdl.handle.net/11244/46950

Kansas State University

11. Petingco, Marvin Carpena. Discrete element method simulation of wheat bulk density.

Degree: PhD, Department of Biological & Agricultural Engineering, 2020, Kansas State University

URL: http://hdl.handle.net/2097/40949

► Bulk density indicates how much weight of material can be packed in a bin, truck, or any container used for storage or transportation. Stored grain… (more)

▼ Bulk density indicates how much weight of material can be packed in a bin, truck, or any container used for storage or transportation. Stored grain bulk density is higher than the standard bushel test weight because of the overburden pressure and handling practices. The material and equipment properties, and widely varying interactions between kernels add to the complexity of analyzing bulk density changes in stored grain. The influence of these factors on wheat bulk density was investigated and wheat bulk density was simulated using the discrete element method (DEM). The objectives of this research were to: (1) experimentally investigate the influence of kernel shape and size on packing ratio and compressibility of wheat, (2) determine the influence of particle shape and contact parameters on DEM-simulated bulk density, (3) simulate using DEM the bulk density of wheat as affected by grain drop height and size distribution, and (4) simulate using DEM the bulk density of wheat as affected by overburden pressure. Laboratory experiments showed that packing ratio (compressibility) had strong positive (negative) linear relationship with sphericity and flatness shape factors but strong negative (positive) linear relationship with elongation shape factor. Also, the higher percentage of mass of larger kernel fraction in a mixture contributed to higher packing ratio and lower compressibility. DEM simulation showed that decreasing aspect ratio and geometrical smoothness of particles increased simulated bulk density of wheat. Among the pseudo-ellipsoidal particle models, the five-sphere particle was the best option to represent wheat particles, while among the contact parameters, the wheat-to-wheat coefficient of static friction and wheat-to-wheat rolling friction had the greatest influence on simulated bulk density. Wheat bulk density as affected by drop height and percentage composition of the three kernel fractions can be simulated accurately using either single-sphere or five-sphere pseudo-ellipsoidal particle, provided that the contact parameters of each particle model representing each size fraction were calibrated individually. DEM simulation of wheat under confined uniaxial compression was implemented to determine the effect of overburden pressure on wheat bulk density. Results showed that the appropriate time step, grid size, and pressure loading rate had to be determined first to avoid instabilities and erroneous results. The DEM simulated bulk densities agreed with the experimental results for overburden pressure below 48kPa and tend to overpredict at higher overburden pressure. This study contributed to better understanding of the influence of particle shape, contact parameters, drop height, overburden pressure, and size distribution on bulk density and provides an approach on how to simulate wheat bulk density using DEM as affected by these factors. These findings can be used in developing accurate models for estimating bulk density and grain packing in bins and other storage structures. Advisors/Committee Members: Mark E. CasadaRonaldo G. MaghirangDonghai Wang.

Subjects/Keywords: Discrete element method; Bulk density; Wheat compressibility; Wheat packing; Particle shape; Particle size distribution

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APA (6^th Edition):

Petingco, M. C. (2020). Discrete element method simulation of wheat bulk density. (Doctoral Dissertation). Kansas State University. Retrieved from http://hdl.handle.net/2097/40949

Chicago Manual of Style (16^th Edition):

Petingco, Marvin Carpena. “Discrete element method simulation of wheat bulk density.” 2020. Doctoral Dissertation, Kansas State University. Accessed March 06, 2021. http://hdl.handle.net/2097/40949.

MLA Handbook (7^th Edition):

Petingco, Marvin Carpena. “Discrete element method simulation of wheat bulk density.” 2020. Web. 06 Mar 2021.

Vancouver:

Petingco MC. Discrete element method simulation of wheat bulk density. [Internet] [Doctoral dissertation]. Kansas State University; 2020. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/2097/40949.

Council of Science Editors:

Petingco MC. Discrete element method simulation of wheat bulk density. [Doctoral Dissertation]. Kansas State University; 2020. Available from: http://hdl.handle.net/2097/40949

University of California – San Diego

12. Beckwith, Frank. An Immersed Reproducing Kernel Particle Method for Modeling Inhomogeneous Media.

Degree: Structural Engineering, 2018, University of California – San Diego

URL: http://www.escholarship.org/uc/item/6j9431x4

► Structures involving multiple materials are difficult for meshfree methods to model accurately due to the strain discontinuity introduced at the material interface. An immersed Reproducing… (more)

Subjects/Keywords: Civil engineering; Fictitious domain; Immersed discretization; Inhomogeneous media; Nitsche's method; Reproducing kernel particle method

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APA (6^th Edition):

Beckwith, F. (2018). An Immersed Reproducing Kernel Particle Method for Modeling Inhomogeneous Media. (Thesis). University of California – San Diego. Retrieved from http://www.escholarship.org/uc/item/6j9431x4

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):

Beckwith, Frank. “An Immersed Reproducing Kernel Particle Method for Modeling Inhomogeneous Media.” 2018. Thesis, University of California – San Diego. Accessed March 06, 2021. http://www.escholarship.org/uc/item/6j9431x4.

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

MLA Handbook (7^th Edition):

Beckwith, Frank. “An Immersed Reproducing Kernel Particle Method for Modeling Inhomogeneous Media.” 2018. Web. 06 Mar 2021.

Vancouver:

Beckwith F. An Immersed Reproducing Kernel Particle Method for Modeling Inhomogeneous Media. [Internet] [Thesis]. University of California – San Diego; 2018. [cited 2021 Mar 06]. Available from: http://www.escholarship.org/uc/item/6j9431x4.

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

Council of Science Editors:

Beckwith F. An Immersed Reproducing Kernel Particle Method for Modeling Inhomogeneous Media. [Thesis]. University of California – San Diego; 2018. Available from: http://www.escholarship.org/uc/item/6j9431x4

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

13. Gleber Nelson Marques. O método Particle-In-Diffuse-Cell: uma abordagem meshfree para simulação de plasmas.

Degree: 2008, Instituto Nacional de Pesquisas Espaciais

URL: http://urlib.net/sid.inpe.br/[email protected]/2008/02.18.20.02

►

This thesis describes an original meshfree formulation for plasmas simulation based on the Particle-In-Cell (PIC) particle model and the Element-Free Galerkin method (EFGM). Recalling the… (more)

▼

This thesis describes an original meshfree formulation for plasmas simulation based on the Particle-In-Cell (PIC) particle model and the Element-Free Galerkin method (EFGM). Recalling the diffuse element concept introduced before the EFGM proposition, we realize the diffuse cell concept, which allowed the development of the Particle-In-Diffuse-Cell (PIDC) formulation. Electrostatic PIC models and the EFGM were revised, as well as the parallelization of PIC codes and collisional models. Despite the ability of easy adaptivity of the meshfree methods, also its robustness for computing the electric field is a very desired feature for PIC models. An interpolating EFGM with the domain truncation technique was rigorously evaluated for the computation of continuous and discontinuous electric fields. PIDC potential applications include complex bi or tri-dimensional geometries, and / or the requirement of frequent mesh refinement, in these scenarios, the PIDC formulation can be seen as a promising new numerical alternative instead of PIC mesh-based methods.

Esta tese descreve uma formulação meshfree inédita para simulação de plasmas via modelo de partículas fundamentada no modelo Particle-In-Cell (PIC) e no método Element-Free Galerkin (MEFG). A partir da revisão do conceito de elemento difuso, precursor do MEFG, chegou-se à concepção da célula difusa, dando origem à formulação denominada Particle-In-Diffuse-Cell (PIDC). Modelos PIC eletrostáticos e o MEFG são revisados para subsidiar a apresentação da formulação do método PIDC, bem como a paralelização de programas PIC e modelos colisionais. Além da característica de fácil adaptatividade dos métodos meshfree, a robustez no cálculo do campo elétrico também é um requisisto bastante desejável em modelos PIC. A abordagem interpolante do MEFG combinada com a técnica de truncamento de domínios, empregada no modelo computacional do PIDC, foi rigorosamente avaliada quanto a acurácia no cálculo de campos elétricos contínuos e descontínuos. O grande potencial de aplicação do PIDC inclui simulações de plasmas envolvendo geometrias complexas bi ou tridimensionais e / ou a necessidade de sucessivos refinamentos de malha, constituindo-se assim, nestes cenários, uma nova e promissora alternativa numérica aos métodos PIC baseados em malha.

Advisors/Committee Members: José Carlos Becceneri, Angelo Pássaro, Stephan Stephany, Fernando Manuel Ramos, Haroldo Fraga de Campos Velho, Vladimir Henrique Baggio Scheid.

Subjects/Keywords: Particle in cell technique; element free Galerkin method; meshfree method; magnetohydrodynamic simulation; plasma dynamics

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APA (6^th Edition):

Marques, G. N. (2008). O método Particle-In-Diffuse-Cell: uma abordagem meshfree para simulação de plasmas. (Thesis). Instituto Nacional de Pesquisas Espaciais. Retrieved from http://urlib.net/sid.inpe.br/[email protected]/2008/02.18.20.02

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):

Marques, Gleber Nelson. “O método Particle-In-Diffuse-Cell: uma abordagem meshfree para simulação de plasmas.” 2008. Thesis, Instituto Nacional de Pesquisas Espaciais. Accessed March 06, 2021. http://urlib.net/sid.inpe.br/[email protected]/2008/02.18.20.02.

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

MLA Handbook (7^th Edition):

Marques, Gleber Nelson. “O método Particle-In-Diffuse-Cell: uma abordagem meshfree para simulação de plasmas.” 2008. Web. 06 Mar 2021.

Vancouver:

Marques GN. O método Particle-In-Diffuse-Cell: uma abordagem meshfree para simulação de plasmas. [Internet] [Thesis]. Instituto Nacional de Pesquisas Espaciais; 2008. [cited 2021 Mar 06]. Available from: http://urlib.net/sid.inpe.br/[email protected]/2008/02.18.20.02.

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

Council of Science Editors:

Marques GN. O método Particle-In-Diffuse-Cell: uma abordagem meshfree para simulação de plasmas. [Thesis]. Instituto Nacional de Pesquisas Espaciais; 2008. Available from: http://urlib.net/sid.inpe.br/[email protected]/2008/02.18.20.02

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

University of Cambridge

14. Lindberg, Casper. Detailed population balance modelling of titanium dioxide nanoparticle synthesis.

Degree: PhD, 2020, University of Cambridge

URL: https://doi.org/10.17863/CAM.55443 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810157

► This thesis develops and applies a new detailed population balance model to study the aerosol synthesis of titanium dioxide nanoparticles. It begins by exploring whether… (more)

▼ This thesis develops and applies a new detailed population balance model to study the aerosol synthesis of titanium dioxide nanoparticles. It begins by exploring whether the morphological data captured by an existing detailed particle model can be used in a milling model to relate particle morphology and ultimately the particle synthesis conditions to the behaviour of particles in the milling process. The study identifies limitations in the existing particle model and informs the development of a new detailed particle model. A new, detailed, geometrical particle model is introduced that tracks the size and position of individual primary particles and their relationship with neighbouring primaries in an aggregate. The particle model forms part of a detailed population balance model that can describe the morphological evolution of aggregate particles under inception, coagulation, growth, sintering and coalescence, while resolving the neck radius, free surface area and volume of each individual primary, as well as the fractal-like structure of each aggregate. The model removes the need to assume a fractal dimension and prefactor when calculating the particle gyration and collision diameters, and permits the visualisation of particles. The process sub-models are tested and the convergence behaviour is investigated for a simple batch reactor test case. The synthesis of TiO2 aggregates from TTIP precursor in a lab-scale hot wall reactor is simulated. A two-step simulation methodology is presented to apply the model to a stagnation flame. The methodology extends an existing two-step method, where a detailed population balance model is applied as a post-processing step to flame profiles obtained from a fully-coupled simulation with gas-phase chemistry, flow dynamics and a simple particle model. The new methodology addresses a previously unidentified issue in employing the post-processing step to simulate flames with steep temperature gradients. A corrective sample volume scaling term is introduced to account for the effect of thermophoresis. Finally, the new detailed particle model and methodology are used to simulate the synthesis of titanium dioxide nano-aggregates in a stagnation flame. Model predictions are evaluated against experimental results by comparing experimental measurements from transmission electron microscopy (TEM) data with identical, simulated quantities. A parametric sensitivity study is performed to investigate key model parameters.

Subjects/Keywords: Population balance modelling; Simulation; Stochastic method; Monte-Carlo method; Detailed particle model; Titanium dioxide; Nanoparticle

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

APA (6^th Edition):

Lindberg, C. (2020). Detailed population balance modelling of titanium dioxide nanoparticle synthesis. (Doctoral Dissertation). University of Cambridge. Retrieved from https://doi.org/10.17863/CAM.55443 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810157

Chicago Manual of Style (16^th Edition):

Lindberg, Casper. “Detailed population balance modelling of titanium dioxide nanoparticle synthesis.” 2020. Doctoral Dissertation, University of Cambridge. Accessed March 06, 2021. https://doi.org/10.17863/CAM.55443 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810157.

MLA Handbook (7^th Edition):

Lindberg, Casper. “Detailed population balance modelling of titanium dioxide nanoparticle synthesis.” 2020. Web. 06 Mar 2021.

Vancouver:

Lindberg C. Detailed population balance modelling of titanium dioxide nanoparticle synthesis. [Internet] [Doctoral dissertation]. University of Cambridge; 2020. [cited 2021 Mar 06]. Available from: https://doi.org/10.17863/CAM.55443 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810157.

Council of Science Editors:

Lindberg C. Detailed population balance modelling of titanium dioxide nanoparticle synthesis. [Doctoral Dissertation]. University of Cambridge; 2020. Available from: https://doi.org/10.17863/CAM.55443 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810157

Delft University of Technology

15. Papakrivopoulos, Vasilis (author). Development and Preliminary Evaluation of the Main Features of the Particle Finite Element Method (PFEM) for Solid Mechanics.

Degree: 2018, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:f269c81c-0f10-4622-8b0f-0bf5bc2227a0

► The Particle Finite Element Method is a numerical tool that has been introduced more than a decade ago for the solution of engineering problems involving… (more)

▼ The Particle Finite Element Method is a numerical tool that has been introduced more than a decade ago for the solution of engineering problems involving large deformations. The method falls under the category of mesh-based particle methods, meaning that all information is stored on moving particles that represent the domain under analysis and a computational mesh is used for the solution of the governing equations. Although the method was initially developed for simulating fluid\hyp{}structure interaction problems, owing to its versatility in handling large deformation and constant changes in domain boundaries and contact interfaces, it has been recently employed for solid mechanics applications. However, the lack of a consistent framework for this kind of problems has lead to different implementations of the method presented in the literature, each with its own special features. The main objective of this thesis is to implement a variation of the Particle Finite Element Method and investigate the efficiency of the different features available in literature. Initially, the meshing procedure of the method was developed, which consists of a Delaunay triangulation for assessing the connectivity of the particles and the {α}-shape method for detection of the boundaries of the different domains. This was followed by an investigation on the influence of the related parameter {α_lim} on the outcome of the analysis; it appears that this choice has an impact on the results, in terms of the recovered domain volumes and the simulation response; this parameter has to be selected with care, with respect to the nature of the examined problem. Volume variations are also observed, caused by element deletion and/or addition during remeshing, which, eventually, lead to mass oscillations. These effects can be mitigated by either adjusting the value of the {α_lim} parameter, refining the particle distribution or prescribing the boundary surface during remeshing, by using a constrained Delaunay triangulation. Another important feature of the PFEM is the treatment of contact, which is, typically, done in literature via employment of an interface mesh. This mesh is generated during remeshing, using the same scheme as for the regular domain meshes, i.e. a Delaunay triangulation and the {α}-shape method, and the generated contact elements are then used to enforce the contact constraints, with a variety of methods. In this work, a simple algorithm that disallows inter-penetration and allows free separation and free movement perpendicular to the contact surfaces was formulated and validated against benchmark solid mechanics problems. The automatic contact detection and interface mesh generation allows for the incorporation of more advanced contact treatment schemes. Transference of information between successive meshes is important in PFEM for solid mechanics, especially when the history of elemental variables, e.g. stresses, is required for capturing the solid material… Advisors/Committee Members: Vardon, Phil (mentor), Hicks, Michael (graduation committee), Pisano, Federico (graduation committee), Gonzalez Acosta, Leon (mentor), Delft University of Technology (degree granting institution).

Subjects/Keywords: Particle Finite Element Method; Numerical Modelling; Solid mechanics; Material Point Method; Remeshing

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

APA (6^th Edition):

Papakrivopoulos, V. (. (2018). Development and Preliminary Evaluation of the Main Features of the Particle Finite Element Method (PFEM) for Solid Mechanics. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:f269c81c-0f10-4622-8b0f-0bf5bc2227a0

Chicago Manual of Style (16^th Edition):

Papakrivopoulos, Vasilis (author). “Development and Preliminary Evaluation of the Main Features of the Particle Finite Element Method (PFEM) for Solid Mechanics.” 2018. Masters Thesis, Delft University of Technology. Accessed March 06, 2021. http://resolver.tudelft.nl/uuid:f269c81c-0f10-4622-8b0f-0bf5bc2227a0.

MLA Handbook (7^th Edition):

Papakrivopoulos, Vasilis (author). “Development and Preliminary Evaluation of the Main Features of the Particle Finite Element Method (PFEM) for Solid Mechanics.” 2018. Web. 06 Mar 2021.

Vancouver:

Papakrivopoulos V(. Development and Preliminary Evaluation of the Main Features of the Particle Finite Element Method (PFEM) for Solid Mechanics. [Internet] [Masters thesis]. Delft University of Technology; 2018. [cited 2021 Mar 06]. Available from: http://resolver.tudelft.nl/uuid:f269c81c-0f10-4622-8b0f-0bf5bc2227a0.

Council of Science Editors:

Papakrivopoulos V(. Development and Preliminary Evaluation of the Main Features of the Particle Finite Element Method (PFEM) for Solid Mechanics. [Masters Thesis]. Delft University of Technology; 2018. Available from: http://resolver.tudelft.nl/uuid:f269c81c-0f10-4622-8b0f-0bf5bc2227a0

Virginia Tech

16. He, Long. Study of Fluid Forces and Heat Transfer on Non-spherical Particles in Assembly Using Particle Resolved Simulation.

Degree: PhD, Mechanical Engineering, 2018, Virginia Tech

URL: http://hdl.handle.net/10919/91400

► Gas-solid flow is fundamental to many industrial processes. Extensive experimental and numerical studies have been devoted to understand the interphase momentum and heat transfer in… (more)

Subjects/Keywords: immersed boundary method; Immersed boundary method; Non-spherical particle; Momentum transfer; Heat transfer; Nusselt number

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

APA (6^th Edition):

He, L. (2018). Study of Fluid Forces and Heat Transfer on Non-spherical Particles in Assembly Using Particle Resolved Simulation. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/91400

Chicago Manual of Style (16^th Edition):

He, Long. “Study of Fluid Forces and Heat Transfer on Non-spherical Particles in Assembly Using Particle Resolved Simulation.” 2018. Doctoral Dissertation, Virginia Tech. Accessed March 06, 2021. http://hdl.handle.net/10919/91400.

MLA Handbook (7^th Edition):

He, Long. “Study of Fluid Forces and Heat Transfer on Non-spherical Particles in Assembly Using Particle Resolved Simulation.” 2018. Web. 06 Mar 2021.

Vancouver:

He L. Study of Fluid Forces and Heat Transfer on Non-spherical Particles in Assembly Using Particle Resolved Simulation. [Internet] [Doctoral dissertation]. Virginia Tech; 2018. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/10919/91400.

Council of Science Editors:

He L. Study of Fluid Forces and Heat Transfer on Non-spherical Particles in Assembly Using Particle Resolved Simulation. [Doctoral Dissertation]. Virginia Tech; 2018. Available from: http://hdl.handle.net/10919/91400

17. Lindberg, Casper. Detailed Population Balance Modelling of Titanium Dioxide Nanoparticle Synthesis.

Degree: PhD, 2020, University of Cambridge

URL: https://www.repository.cam.ac.uk/handle/1810/308352

► This thesis develops and applies a new detailed population balance model to study the aerosol synthesis of titanium dioxide nanoparticles. It begins by exploring whether… (more)

▼ This thesis develops and applies a new detailed population balance model to study the aerosol synthesis of titanium dioxide nanoparticles. It begins by exploring whether the morphological data captured by an existing detailed particle model can be used in a milling model to relate particle morphology and ultimately the particle synthesis conditions to the behaviour of particles in the milling process. The study identifies limitations in the existing particle model and informs the development of a new detailed particle model. A new, detailed, geometrical particle model is introduced that tracks the size and position of individual primary particles and their relationship with neighbouring primaries in an aggregate. The particle model forms part of a detailed population balance model that can describe the morphological evolution of aggregate particles under inception, coagulation, growth, sintering and coalescence, while resolving the neck radius, free surface area and volume of each individual primary, as well as the fractal-like structure of each aggregate. The model removes the need to assume a fractal dimension and prefactor when calculating the particle gyration and collision diameters, and permits the visualisation of particles. The process sub-models are tested and the convergence behaviour is investigated for a simple batch reactor test case. The synthesis of TiO2 aggregates from TTIP precursor in a lab-scale hot wall reactor is simulated. A two-step simulation methodology is presented to apply the model to a stagnation flame. The methodology extends an existing two-step method, where a detailed population balance model is applied as a post-processing step to flame profiles obtained from a fully-coupled simulation with gas-phase chemistry, flow dynamics and a simple particle model. The new methodology addresses a previously unidentified issue in employing the post-processing step to simulate flames with steep temperature gradients. A corrective sample volume scaling term is introduced to account for the effect of thermophoresis. Finally, the new detailed particle model and methodology are used to simulate the synthesis of titanium dioxide nano-aggregates in a stagnation flame. Model predictions are evaluated against experimental results by comparing experimental measurements from transmission electron microscopy (TEM) data with identical, simulated quantities. A parametric sensitivity study is performed to investigate key model parameters.

Subjects/Keywords: Population balance modelling; Simulation; Stochastic method; Monte-Carlo method; Detailed particle model; Titanium dioxide; Nanoparticle

10 more images…

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

APA (6^th Edition):

Lindberg, C. (2020). Detailed Population Balance Modelling of Titanium Dioxide Nanoparticle Synthesis. (Doctoral Dissertation). University of Cambridge. Retrieved from https://www.repository.cam.ac.uk/handle/1810/308352

Chicago Manual of Style (16^th Edition):

Lindberg, Casper. “Detailed Population Balance Modelling of Titanium Dioxide Nanoparticle Synthesis.” 2020. Doctoral Dissertation, University of Cambridge. Accessed March 06, 2021. https://www.repository.cam.ac.uk/handle/1810/308352.

MLA Handbook (7^th Edition):

Lindberg, Casper. “Detailed Population Balance Modelling of Titanium Dioxide Nanoparticle Synthesis.” 2020. Web. 06 Mar 2021.

Vancouver:

Lindberg C. Detailed Population Balance Modelling of Titanium Dioxide Nanoparticle Synthesis. [Internet] [Doctoral dissertation]. University of Cambridge; 2020. [cited 2021 Mar 06]. Available from: https://www.repository.cam.ac.uk/handle/1810/308352.

Council of Science Editors:

Lindberg C. Detailed Population Balance Modelling of Titanium Dioxide Nanoparticle Synthesis. [Doctoral Dissertation]. University of Cambridge; 2020. Available from: https://www.repository.cam.ac.uk/handle/1810/308352

University of Utah

18. Mason, Matthew Scott. Aerothermoelastic modeling and simulation of aerospace vehicles using particle-based methods.

Degree: PhD, Mechanical Engineering, 2015, University of Utah

URL: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/3833/rec/169

► As hypersonic aerospace vehicles are designed to increased performance specifications utilizing lighter weight, higher strength materials, fluid-structural interaction (FSI) effects become increasingly important to model,… (more)

▼ As hypersonic aerospace vehicles are designed to increased performance specifications utilizing lighter weight, higher strength materials, fluid-structural interaction (FSI) effects become increasingly important to model, especially considering the increasing use of numerical models in many phases of design. When a fluid flows over a solid, a force is imparted on the solid and the solid deforms. This deformation, in turn, causes a change in the fluid flow field which modifies the force distribution on the structure. This FSI induced deformation is a primary area of study within the field of aeroelasticity. To further complicate the matter, thermodynamic and chemical effects are vitally important to model in the hypersonic flow regime. Traditionally, two separate numerical models are utilized to model the fluid and solid phases and a coupling algorithm accomplishes the task of modeling FSI. Coupling between the two solvers introduces numerical inaccuracies, inefficiencies, and for many mesh-based solvers, large deformations cannot be modeled. For this research, a combined Eulerian grid-based and Lagrangian particle-based solver known as the Material Point Method (MPM) is introduced and defined from prior research by others, and the particular MPM numerical code utilized in this research is outlined. The code combines the two separate solvers into a single numerical algorithm with separate constitutive relations for the fluid and solid phase, thereby allowing FSI modeling within a single computational framework. A limiter is applied to reduce numerical noise and oscillations around shock and expansion waves and exhibits a large reduction in oscillation amplitude and frequency. A Fourier's Law of Conduction heat transfer algorithm is implemented for heat transfer at a fluid-structure interface. The results from this heat transfer algorithm are compared with an independently developed numerical code for the single ramp case and experimental data for the double cone case. Finally, a reacting flow model is exhibited, the results are compared to other numerical solutions for verification and recommendations are made for further research.

Subjects/Keywords: Computational Fluid Dynamics; Hypersonic; Material Point Method; Particle-Based Methods

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

APA (6^th Edition):

Mason, M. S. (2015). Aerothermoelastic modeling and simulation of aerospace vehicles using particle-based methods. (Doctoral Dissertation). University of Utah. Retrieved from http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/3833/rec/169

Chicago Manual of Style (16^th Edition):

Mason, Matthew Scott. “Aerothermoelastic modeling and simulation of aerospace vehicles using particle-based methods.” 2015. Doctoral Dissertation, University of Utah. Accessed March 06, 2021. http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/3833/rec/169.

MLA Handbook (7^th Edition):

Mason, Matthew Scott. “Aerothermoelastic modeling and simulation of aerospace vehicles using particle-based methods.” 2015. Web. 06 Mar 2021.

Vancouver:

Mason MS. Aerothermoelastic modeling and simulation of aerospace vehicles using particle-based methods. [Internet] [Doctoral dissertation]. University of Utah; 2015. [cited 2021 Mar 06]. Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/3833/rec/169.

Council of Science Editors:

Mason MS. Aerothermoelastic modeling and simulation of aerospace vehicles using particle-based methods. [Doctoral Dissertation]. University of Utah; 2015. Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/3833/rec/169

UCLA

19. Roth, Michael Jason. A Reproducing Kernel Particle Hydrodynamic Formulation for Modeling Strong Shock Effects in Nonlinear Solids.

Degree: Civil Engineering, 2013, UCLA

URL: http://www.escholarship.org/uc/item/9wb7115w

► Many of today's challenging engineering and scientific problems involve the response of nonlinear solid materials to high-rate dynamic loading. Accompanying hydrodynamic effects are crucial, where… (more)

▼ Many of today's challenging engineering and scientific problems involve the response of nonlinear solid materials to high-rate dynamic loading. Accompanying hydrodynamic effects are crucial, where the shock-driven pressure dominates material response. In this work a hydrodynamic meshfree formulation is developed under the Lagrangian reproducing kernel particle method (RKPM) framework. The volumetric stress divergence is enhanced to capture the high-pressure shock response, and the deviatoric portion is retained to describe strength effects of the solid material. A shock modeling formulation for scalar conservation laws is first constructed. In the scalar formulation the reproducing kernel particle method is formulated to address two key shock modeling issues, that is, accurate representation of the essential shock physics and control of the numerical oscillations due to Gibbs phenomenon at the jump. This is achieved by forming a smoothed flux divergence under the meshfree stabilized conforming nodal integration (SCNI) framework, and then enriching the flux divergence with a Riemann solution. The Riemann-enriched flux divergence is embedded into a velocity corrector adaptively applied at the shock front. As a consequence the shock solution is locally corrected while the smooth solution away from the shock is unaffected. For shocks in solids, developments from the scalar formulation were extended to the Cauchy's equation of motion. Shock effects in solids are pressure dominated, so that the shock solution is enhanced through the volumetric stress divergence. The volumetric stress divergence correction is formulated using a Rankine-Hugoniot enriched Riemann solution that introduces the essential shock physics to the formulation. Oscillation control is introduced through the state and field variable approximations that utilize the Riemann problem initial conditions, and therefore non-physical numerical parameters and length scales required in the traditional artificial viscosity technique are avoided. Further, because the proposed method for oscillation control is linked to the essential physics, the two key issues for accurate shock modeling are addressed in a unified and consistent way. For the nonlinear solids formulation, several benchmark problems are solved and the numerical results are verified by comparison to experimental data or analytical solutions. A range of shock conditions are studied to show the versatility of the proposed method for modeling conditions ranging from weak elastic-plastic shocks to strong shocks generated by hypervelocity impact.

Subjects/Keywords: Civil engineering; hydrodynamic; meshfree; nonlinear solids; reproducing kernel particle method; shock

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APA (6^th Edition):

Roth, M. J. (2013). A Reproducing Kernel Particle Hydrodynamic Formulation for Modeling Strong Shock Effects in Nonlinear Solids. (Thesis). UCLA. Retrieved from http://www.escholarship.org/uc/item/9wb7115w

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):

Roth, Michael Jason. “A Reproducing Kernel Particle Hydrodynamic Formulation for Modeling Strong Shock Effects in Nonlinear Solids.” 2013. Thesis, UCLA. Accessed March 06, 2021. http://www.escholarship.org/uc/item/9wb7115w.

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

MLA Handbook (7^th Edition):

Roth, Michael Jason. “A Reproducing Kernel Particle Hydrodynamic Formulation for Modeling Strong Shock Effects in Nonlinear Solids.” 2013. Web. 06 Mar 2021.

Vancouver:

Roth MJ. A Reproducing Kernel Particle Hydrodynamic Formulation for Modeling Strong Shock Effects in Nonlinear Solids. [Internet] [Thesis]. UCLA; 2013. [cited 2021 Mar 06]. Available from: http://www.escholarship.org/uc/item/9wb7115w.

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

Council of Science Editors:

Roth MJ. A Reproducing Kernel Particle Hydrodynamic Formulation for Modeling Strong Shock Effects in Nonlinear Solids. [Thesis]. UCLA; 2013. Available from: http://www.escholarship.org/uc/item/9wb7115w

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

INP Toulouse

20. Izard, Edouard. Modélisation numérique des écoulements granulaires denses immergés dans un fluide : Numerical modeling of dense granular flows immersed in a fluid.

Degree: Docteur es, Dynamique des fluides, 2014, INP Toulouse

URL: http://www.theses.fr/2014INPT0088

►

Ce travail de thèse concerne la modélisation numérique fine des processus locaux dans le transport sédimentaire, à l'échelle d'un à plusieurs centaines de grains. Une… (more)

▼

Ce travail de thèse concerne la modélisation numérique fine des processus locaux dans le transport sédimentaire, à l'échelle d'un à plusieurs centaines de grains. Une méthode aux éléments discrets (DEM) basée sur la méthode dite des sphères molles et prenant en compte les contacts entre les grains a été développée et couplée à une méthode de frontière immergée (IBM) qui calcule l'écoulement autour d'objets solides mobiles dans un fluide Newtonien incompressible. Dans ce couplage, une force de lubrification est incluse pour représenter les interactions entre le fluide et les particules proches d'un contact. Il est montré que la méthode numérique reproduit de manière satisfaisante le coefficient de restitution effective mesuré dans des expériences de rebonds normal et oblique d'un grain sur un plan, ainsi que de rebond entre deux grains dans un fluide visqueux. Deux modèles analytiques associés au phénomène de rebond sont proposés et montrent l'importance de la rugosité de surface du grain et du nombre de Stokes sur le phénomène. La méthode numérique est ensuite utilisée pour simuler deux configurations tridimensionnelles d'écoulements granulaires pilotés par la gravité en milieu fluide : l'avalanche de grains sur un plan incliné rugueux et l'effondrement d'une colonne de grains. Dans le premier cas, les résultats permettent de caractériser les différents régimes d'écoulement granulaires (visqueux, inertiel et sec) observés dans les expériences en fonction du rapport de masse volumique grain-fluide et du nombre de Stokes. En particulier, les simulations apportent des informations originales quant aux profils de vitesse de grains et du fluide ainsi qu'aux forces prédominantes dans chacun des régimes. Dans le second cas, les résultats sont en bon accord avec les expériences et le mécanisme dit de « pore pressure feedback », qui dépend de la compacité initiale de la colonne, est pour la première fois observé dans des simulations numériques directes.

This work deals with direct numerical simulations of sediment transport at the scale of O(103) grains. A soft-sphere discrete element method (DEM) taking into account grain contacts is developed and coupled to an immersed boundary method (IBM) which computes the flow around moving solid objects in an incompressible Newtonian fluid. A lubrication force is added for representing fluid-particles interaction near contact. The numerical method is shown to adequately reproduce the effective coefficient of restitution measured in experiments of the normal and oblique rebound of a grain on a plane and the rebound between two grains in a viscous fluid. Two analytical models are proposed and highlight the importance of the grain roughness and Stokes number on the rebound phenomenon. This numerical method is then used for simulating two three-dimensional configurations of gravity-driven dense granular flow in a fluid, namely the granular avalanche on a rough inclined plane and the collapse of a granular column. In the first case, results allow to characterize the granular flow regimes…

Advisors/Committee Members: Bonometti, Thomas (thesis director), Eiff, Olivier (thesis director).

Subjects/Keywords: Méthode numérique; Ecoulement fluide-particule; Computational method; Particle-fluid flow

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

APA (6^th Edition):

Izard, E. (2014). Modélisation numérique des écoulements granulaires denses immergés dans un fluide : Numerical modeling of dense granular flows immersed in a fluid. (Doctoral Dissertation). INP Toulouse. Retrieved from http://www.theses.fr/2014INPT0088

Chicago Manual of Style (16^th Edition):

Izard, Edouard. “Modélisation numérique des écoulements granulaires denses immergés dans un fluide : Numerical modeling of dense granular flows immersed in a fluid.” 2014. Doctoral Dissertation, INP Toulouse. Accessed March 06, 2021. http://www.theses.fr/2014INPT0088.

MLA Handbook (7^th Edition):

Izard, Edouard. “Modélisation numérique des écoulements granulaires denses immergés dans un fluide : Numerical modeling of dense granular flows immersed in a fluid.” 2014. Web. 06 Mar 2021.

Vancouver:

Izard E. Modélisation numérique des écoulements granulaires denses immergés dans un fluide : Numerical modeling of dense granular flows immersed in a fluid. [Internet] [Doctoral dissertation]. INP Toulouse; 2014. [cited 2021 Mar 06]. Available from: http://www.theses.fr/2014INPT0088.

Council of Science Editors:

Izard E. Modélisation numérique des écoulements granulaires denses immergés dans un fluide : Numerical modeling of dense granular flows immersed in a fluid. [Doctoral Dissertation]. INP Toulouse; 2014. Available from: http://www.theses.fr/2014INPT0088

Université Catholique de Louvain

21. Gillis, Thomas. Accurate and efficient treatment of solid boundaries for the Vortex Particle-Mesh method.

Degree: 2019, Université Catholique de Louvain

URL: http://hdl.handle.net/2078.1/217851

►

The Vortex Particle-Mesh method has been gaining popularity for many advection-dominated flow simulations, such as wake studies at high Reynolds numbers and external aerodynamics. However,… (more)

▼

The Vortex Particle-Mesh method has been gaining popularity for many advection-dominated flow simulations, such as wake studies at high Reynolds numbers and external aerodynamics. However, the handling of inner solid boundaries remains an open challenge as the formulation of the boundary condition for the vorticity is not as straightforward as in a classical velocity-pressure formulation. This complexity is further increased since the method relies on a non-body-conforming Cartesian mesh; hence the obstacle may intersect the grid at arbitrary locations. In such a setting, several numerical techniques have been proposed for immersing the geometry into the Cartesian mesh. In this work, we investigate two approaches aimed at addressing this problem: the iterative penalization technique and the Immersed Interface treatment. The iterative penalization enforces the body contribution by adding an additional source term to the Navier-Stokes equations. It results in a non-intrusive way to handle immersed boundaries, yet it leads to inaccurate results. On the contrary, the Immersed Interface treatment is sharp and accurate, as it handles the interface discontinuities on the grid through the evaluation of jumps so as to maintain the order of convergence of the finite difference stencil used. We apply the Immersed Interface tool to the Vortex Particle-Mesh method and prove its accuracy and efficiency on 2D and 3D benchmarks. This method is more intrusive than the iterative penalization approach, yet it is less computationally expensive. It also enables the computation of wall quantities, which are mandatory for fluid-structure interaction applications. Our approach is the first of its kind that enables a flexible, accurate and efficient treatment of solid boundaries for the Vortex Particle-Mesh framework.

(FSA - Sciences de l'ingénieur) – UCL, 2019

Advisors/Committee Members: UCL - SST/IMMC/TFL - Thermodynamics and fluid mechanics, UCL - Ecole Polytechnique de Louvain, Chatelain, Philippe, Winckelmans, Grégoire, Pardoen, Thomas, Remacle, Jean-François, Marichal, Yves, van Rees, Wim, Poncet, Philippe.

Subjects/Keywords: Immersed Interface; Vortex Particle-Mesh method; Immersed boundaries; Iterative penalization

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

APA (6^th Edition):

Gillis, T. (2019). Accurate and efficient treatment of solid boundaries for the Vortex Particle-Mesh method. (Thesis). Université Catholique de Louvain. Retrieved from http://hdl.handle.net/2078.1/217851

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):

Gillis, Thomas. “Accurate and efficient treatment of solid boundaries for the Vortex Particle-Mesh method.” 2019. Thesis, Université Catholique de Louvain. Accessed March 06, 2021. http://hdl.handle.net/2078.1/217851.

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

MLA Handbook (7^th Edition):

Gillis, Thomas. “Accurate and efficient treatment of solid boundaries for the Vortex Particle-Mesh method.” 2019. Web. 06 Mar 2021.

Vancouver:

Gillis T. Accurate and efficient treatment of solid boundaries for the Vortex Particle-Mesh method. [Internet] [Thesis]. Université Catholique de Louvain; 2019. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/2078.1/217851.

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

Council of Science Editors:

Gillis T. Accurate and efficient treatment of solid boundaries for the Vortex Particle-Mesh method. [Thesis]. Université Catholique de Louvain; 2019. Available from: http://hdl.handle.net/2078.1/217851

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

22. Zhou, Changtai. Theoretical and numerical modelling of the anisotropic behaviour of jointed rocks.

Degree: 2019, University of Adelaide

URL: http://hdl.handle.net/2440/119874

► In nature, various forms of rock anisotropy are widely pre-existing discontinuities such as bedding planes, joints, weak layers and cleavages. Rock anisotropic characteristics are in… (more)

▼ In nature, various forms of rock anisotropy are widely pre-existing discontinuities such as bedding planes, joints, weak layers and cleavages. Rock anisotropic characteristics are in general critical for the stability of surface or underground rock excavations. The goal of this work is to investigate the anisotropic behaviour of jointed rock masses using theoretical and numerical modelling methods. In particular, discrete element modelling using flat jointed bonded particle model (FJM) was used in this research. A systematic micro-parameter calibration method for FJM was proposed first in this work to overcome the limitations of traditional approach, which essentially is a time-consuming tedious trial and error process. The relationships between the FJM micro-parameters and constitutive parameters, as well as macro-mechanical rock properties were first established through dimensionless analysis. Sensitivity and regression analyses were then conducted to quantify their relationships, using results from numerical simulations. The proposed method was demonstrated to be robust and effective based on the macro-mechanical property validation of four different types of rocks. The application of FJM to capture the load rate-dependent mechanical properties of rock materials was investigated. The results were cross-validated with experimental measurements, which indicated that FJM can model the dynamic behaviour of rocks from quasi-static to medium strain rate range. FJM, in combination with smooth joint model (SJM) used to model discontinuities, were then used to study the dynamic behaviour of rocks with a persistent joint at different orientations. A strength prediction model for dynamic UCS of a specimen containing a persistent joint at different orientations were proposed and the coefficients of the proposed equation were quantified based on numerical simulation results. The proposed model was shown to be capable of predicting VII the rate-dependent UCS of a jointed rock. Finally, the strength reduction of a jointed rock was further investigated using the statistical damage model approach based on the commonly used Weibull distribution, where the Jaeger’s and modified Hoek-Brown failure criteria were incorporated in the derived model. The proposed damage model was validated using published experimental data and numerical simulation results of FJM. Results indicated that parameter m only depends on strain parameter k, which is directly proportional to the increase of the failure strain, while parameter F0 is indirectly related to the strength of the jointed rock. In addition, joint stiffness can be easily incorporated in the proposed damage model, which has significant influence on the damage variable D, damage evolution rate Dr and rock mass deformation modulus. Outcomes of this research help us to understand better the influences of discontinuities on the mechanical behaviour of jointed rock masses. Advisors/Committee Members: Xu, Chaoshui (advisor), School of Civil, Environmental and Mining Engineering (school).

Subjects/Keywords: discrete element method; bonded-particle model; loading rate; anisotropy; damage model

10 more images…

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

APA (6^th Edition):

Zhou, C. (2019). Theoretical and numerical modelling of the anisotropic behaviour of jointed rocks. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/119874

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):

Zhou, Changtai. “Theoretical and numerical modelling of the anisotropic behaviour of jointed rocks.” 2019. Thesis, University of Adelaide. Accessed March 06, 2021. http://hdl.handle.net/2440/119874.

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

MLA Handbook (7^th Edition):

Zhou, Changtai. “Theoretical and numerical modelling of the anisotropic behaviour of jointed rocks.” 2019. Web. 06 Mar 2021.

Vancouver:

Zhou C. Theoretical and numerical modelling of the anisotropic behaviour of jointed rocks. [Internet] [Thesis]. University of Adelaide; 2019. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/2440/119874.

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

Council of Science Editors:

Zhou C. Theoretical and numerical modelling of the anisotropic behaviour of jointed rocks. [Thesis]. University of Adelaide; 2019. Available from: http://hdl.handle.net/2440/119874

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

Université Catholique de Louvain

23. Lonfils, Timothée. Vortex particle-mesh with combined immersed boundary and mesh refinement techniques : application to bluff-body and wake-vortex flows.

Degree: 2011, Université Catholique de Louvain

URL: http://hdl.handle.net/2078.1/107701

►

The present work joins a global effort in the development of efficient and accurate numerical tools for the simulation of complex fluid flows. More specifically,… (more)

▼

The present work joins a global effort in the development of efficient and accurate numerical tools for the simulation of complex fluid flows. More specifically, we focus on unsteady external flows, a fluid dynamics discipline which actually pervades applied sciences and engineering. These are the flow encountered in aircraft or car aerodynamics, wind energy, biological locomotion, etc. In the problems addressed here, we assume that the flow is incompressible and that the inertial forces dominate the viscous stresses: we are dealing with both moderate and high Reynolds number flows. Furthermore, the present work treats the flow equations in a very distinct approach. We use a vortex particle-mesh (VPM) method, which belongs to the broader class of “vortex methods”. Such methods use the vorticity-velocity formulation of the Navier-Stokes equations, rather than the velocity-pressure formulation: the vorticity field is thus the primary variable. The major advantage comes from the compactness of the vorticity field for external flows and wakes. A limited number of particles is thus required to discretize the entire flow. First, an immersed boundary technique has been developed and adapted to capture the flow past arbitrary shape bodies. The motivation is to benefit from the enhanced efficiency provided by the VPM method in terms of computational cost (as shown in previous works). The required Poisson equation is solved using an efficient grid-based solver combined with a parallel fast multipole method (which provides the required boundary conditions on each subdomain). Second, an accurate approach handling hierarchically refined meshes has been developed. We use both grid patches and particles of varying resolution. The originality of this work is the combination of the handling of multiple flow resolutions together with a full 3-D VPM Navier-Stokes solver to compute incompressible flows. This method also benefits from the versatility of the parallel fast multipole method which enables the efficient solution of the Poisson equation and straightforward domain decomposition. We have also demonstrated the potential of the mesh refinement technique on a Large-Eddy Simulation of a turbulent vortex wake rollup at very high Reynolds number.

(FSA 3) – UCL, 2011

Advisors/Committee Members: UCL - SST/IMMC/TFL - Thermodynamics and fluid mechanics, Winckelmans, Grégoire, Pardoen, Thomas, Chatelain, Philippe, Koumoutsakos, Petros, Geuzaine, Philippe, Remacle, Jean-François.

Subjects/Keywords: Vortex particle-mesh method; Immersed boundary; Mesh refinement; Vortical flows

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

APA (6^th Edition):

Lonfils, T. (2011). Vortex particle-mesh with combined immersed boundary and mesh refinement techniques : application to bluff-body and wake-vortex flows. (Thesis). Université Catholique de Louvain. Retrieved from http://hdl.handle.net/2078.1/107701

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):

Lonfils, Timothée. “Vortex particle-mesh with combined immersed boundary and mesh refinement techniques : application to bluff-body and wake-vortex flows.” 2011. Thesis, Université Catholique de Louvain. Accessed March 06, 2021. http://hdl.handle.net/2078.1/107701.

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

MLA Handbook (7^th Edition):

Lonfils, Timothée. “Vortex particle-mesh with combined immersed boundary and mesh refinement techniques : application to bluff-body and wake-vortex flows.” 2011. Web. 06 Mar 2021.

Vancouver:

Lonfils T. Vortex particle-mesh with combined immersed boundary and mesh refinement techniques : application to bluff-body and wake-vortex flows. [Internet] [Thesis]. Université Catholique de Louvain; 2011. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/2078.1/107701.

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

Council of Science Editors:

Lonfils T. Vortex particle-mesh with combined immersed boundary and mesh refinement techniques : application to bluff-body and wake-vortex flows. [Thesis]. Université Catholique de Louvain; 2011. Available from: http://hdl.handle.net/2078.1/107701

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

Université Catholique de Louvain

24. Beluffi, Camille. Search for rare processes with a Z+bb signature at the LHC, using the matrix element method.

Degree: 2015, Université Catholique de Louvain

URL: http://hdl.handle.net/2078.1/165986

►

This talk presents a detailed study of the final state with the Z boson decaying into two leptons, produced in the CMS detector at the… (more)

Subjects/Keywords: Particle physics; Higgs boson; Matrix element method; LHC; CMS

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

APA (6^th Edition):

Beluffi, C. (2015). Search for rare processes with a Z+bb signature at the LHC, using the matrix element method. (Thesis). Université Catholique de Louvain. Retrieved from http://hdl.handle.net/2078.1/165986

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):

Beluffi, Camille. “Search for rare processes with a Z+bb signature at the LHC, using the matrix element method.” 2015. Thesis, Université Catholique de Louvain. Accessed March 06, 2021. http://hdl.handle.net/2078.1/165986.

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

MLA Handbook (7^th Edition):

Beluffi, Camille. “Search for rare processes with a Z+bb signature at the LHC, using the matrix element method.” 2015. Web. 06 Mar 2021.

Vancouver:

Beluffi C. Search for rare processes with a Z+bb signature at the LHC, using the matrix element method. [Internet] [Thesis]. Université Catholique de Louvain; 2015. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/2078.1/165986.

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

Council of Science Editors:

Beluffi C. Search for rare processes with a Z+bb signature at the LHC, using the matrix element method. [Thesis]. Université Catholique de Louvain; 2015. Available from: http://hdl.handle.net/2078.1/165986

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

Delft University of Technology

25. Bagherzadeh, M. (author). Modelling Single Particle Settlement by CFD-DEM Coupling Method.

Degree: 2014, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:04758dc9-97c8-4449-9556-501d6dd778bb

► Dust liberation (a gas-solid two phase problem) is a highly complicated phenomenon to be studied due to great number of variables to be considered, so… (more)

▼ Dust liberation (a gas-solid two phase problem) is a highly complicated phenomenon to be studied due to great number of variables to be considered, so any related theoretical or numerical simulation is forced to implement many simplifications. Furthermore, there are numerous methods to study such a problem one of them is the newly introduced CFD-DEM coupling method. This method is expected to be used extensively in near future; therefore, it is essential to have an understanding about its applicability, strong points and shortcomings to be able to model complex problems such as dust liberation. Accordingly, this research is aiming to model single particle settlement (SPS) as the simplest version of dust liberation problem using CFD-DEM coupling method to comprehend both the SPS problem and the method. To reach this goal three main steps has been taken. In the first step the focus is on understanding the single particle settlement problem. In settlement of a single particle two sorts of forces play roles, driving forces and damping forces. The only driving force is the force of gravity; damping forces, which are opposing the gravity force, are buoyancy, drag, virtual mass, and Basset and lift forces. Results indicate that buoyancy as well as drag force are most influential damping forces. Basset and virtual mass forces are important in the transient phase of the problem only and if the ratio of fluid density to particle density is smaller than a certain value (10-3), the influence of these forces in transient phase as well as steady phase is negligible. In the second step, reasons why CFD-DEM coupling method is preferred for modeling SPS is elaborated. Based on the final application of this thesis, which is modelling of dust liberation phenomenon for research purposes, three criteria are formulated to identify the suitable method. Firstly, the method should be able to study the microscopic mechanisms; secondly, it should be capable of handling particle-particle and particle-wall collisions. Finally, the needed computational effort should be at least in acceptable range. Considering these criteria, the CFD-DEM coupling method has been chosen because of its ability to study microscopic mechanisms, its capability in capturing the particle interactions, and its acceptable computational effort. In the final step, the performance of CFD-DEM coupling method is evaluated. To do so, the numerical results have been compared to experimental and analytical results. In the calibration step, the influential parameters such as governing equation model, void fraction model and drag models have been studied and the most appropriate ones have been chosen. In the verification step, results of the numerical model are compared to other experimental cases with different fluid properties. Consequently, in the phase of validation, results of the numerical model are compared to analytical results of another problem with different particle size, geometry and fluid. Based on the observations, it can be concluded that CFD-DEM coupling method can… Advisors/Committee Members: Schott, D.L. (mentor), Al-Khoury, R. (mentor).

Subjects/Keywords: single particle settlement; computational fluid dynamics; discrete element method

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APA (6^th Edition):

Bagherzadeh, M. (. (2014). Modelling Single Particle Settlement by CFD-DEM Coupling Method. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:04758dc9-97c8-4449-9556-501d6dd778bb

Chicago Manual of Style (16^th Edition):

Bagherzadeh, M (author). “Modelling Single Particle Settlement by CFD-DEM Coupling Method.” 2014. Masters Thesis, Delft University of Technology. Accessed March 06, 2021. http://resolver.tudelft.nl/uuid:04758dc9-97c8-4449-9556-501d6dd778bb.

MLA Handbook (7^th Edition):

Bagherzadeh, M (author). “Modelling Single Particle Settlement by CFD-DEM Coupling Method.” 2014. Web. 06 Mar 2021.

Vancouver:

Bagherzadeh M(. Modelling Single Particle Settlement by CFD-DEM Coupling Method. [Internet] [Masters thesis]. Delft University of Technology; 2014. [cited 2021 Mar 06]. Available from: http://resolver.tudelft.nl/uuid:04758dc9-97c8-4449-9556-501d6dd778bb.

Council of Science Editors:

Bagherzadeh M(. Modelling Single Particle Settlement by CFD-DEM Coupling Method. [Masters Thesis]. Delft University of Technology; 2014. Available from: http://resolver.tudelft.nl/uuid:04758dc9-97c8-4449-9556-501d6dd778bb

Delft University of Technology

26. Mehmood, Junaid (author). Study of Rheological Behaviour of Spherocylindrical Particle Suspension via CFD-DEM: Formulation of Stress-Closure for Industrial Fluidized Bed Simulation.

Degree: 2018, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:6e8e2b5c-7577-4a29-8085-99c74c604325

►

While colloidal suspensions of non-spherical particles have been studied relatively extensively, granular suspensions of non-spherical particles are rarely studied. The rheological behaviour of elongated granular… (more)

Subjects/Keywords: Discrete Element Method; CFD-DEM Coupling; Spherocylindrical Particle; Rheology

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APA (6^th Edition):

Mehmood, J. (. (2018). Study of Rheological Behaviour of Spherocylindrical Particle Suspension via CFD-DEM: Formulation of Stress-Closure for Industrial Fluidized Bed Simulation. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:6e8e2b5c-7577-4a29-8085-99c74c604325

Chicago Manual of Style (16^th Edition):

Mehmood, Junaid (author). “Study of Rheological Behaviour of Spherocylindrical Particle Suspension via CFD-DEM: Formulation of Stress-Closure for Industrial Fluidized Bed Simulation.” 2018. Masters Thesis, Delft University of Technology. Accessed March 06, 2021. http://resolver.tudelft.nl/uuid:6e8e2b5c-7577-4a29-8085-99c74c604325.

MLA Handbook (7^th Edition):

Mehmood, Junaid (author). “Study of Rheological Behaviour of Spherocylindrical Particle Suspension via CFD-DEM: Formulation of Stress-Closure for Industrial Fluidized Bed Simulation.” 2018. Web. 06 Mar 2021.

Vancouver:

Mehmood J(. Study of Rheological Behaviour of Spherocylindrical Particle Suspension via CFD-DEM: Formulation of Stress-Closure for Industrial Fluidized Bed Simulation. [Internet] [Masters thesis]. Delft University of Technology; 2018. [cited 2021 Mar 06]. Available from: http://resolver.tudelft.nl/uuid:6e8e2b5c-7577-4a29-8085-99c74c604325.

Council of Science Editors:

Mehmood J(. Study of Rheological Behaviour of Spherocylindrical Particle Suspension via CFD-DEM: Formulation of Stress-Closure for Industrial Fluidized Bed Simulation. [Masters Thesis]. Delft University of Technology; 2018. Available from: http://resolver.tudelft.nl/uuid:6e8e2b5c-7577-4a29-8085-99c74c604325

University of the Western Cape

27. Cunnama, Daniel. Galaxy Evolution and Cosmology using Supercomputer Simulations by Daniel Cunnama .

Degree: 2013, University of the Western Cape

URL: http://hdl.handle.net/11394/4042

► Numerical simulations play a crucial role in testing current cosmological models of the formation and evolution of the cosmic structure observed in the modern Universe.… (more)

▼ Numerical simulations play a crucial role in testing current cosmological models of the formation and evolution of the cosmic structure observed in the modern Universe. Simulations of the collapse of both baryonic and non-baryonic matter under the influence of gravity have yielded important results in our understanding of the large scale structure of the Universe. In addition to the underlying large scale structure, simulations which include gas dynamics can give us valuable insight into, and allow us to make testable predictions on, the nature and distribution of baryonic matter on a wide range of scales. In this work we give an overview of cosmological simulations and the methods employed in the solution of many body problems. We then present three projects focusing on scales ranging from individual galaxies to the cosmic web connecting clusters of galaxies thereby demonstrating the potential and diversity of numerical simulations in the fields of cosmology and astrophysics. We firstly investigate the environmental dependance of neutral hydrogen in the intergalactic medium by utilising high resolution cosmological hydrodynamic simulations in Chapter 3. We find that the extent of the neutral hydrogen radial profile is dependant on both the environment of the galaxy and its classification within the group ie. whether it is a central or satellite galaxy. We investigate whether this effect could arise from ram pressure forces exerted on the galaxies and find good agreement between galaxies experiencing high ram pressure forces and those with a low neutral hydrogen content. In Chapter 4 we investigate the velocity–shape alignment of clusters in a dark matter only simulation and the effect of such an alignment on measurements of the kinetic Sunyaev–Zeldovich (kSZ) effect. We find an alignment not only exists but can lead to an enhancement in the kSZ signal of up to 60% when the cluster is orientated along the line-of-sight. Finally we attempt to identify shocked gas in clusters and filaments using intermediate resolution cosmological hydrodynamic simulations in Chapter 5 with a view to predicting the synchrotron emission from these areas, something that may be detectable with the Square Kilometer Array.

Subjects/Keywords: Dark matter; dark energy; direct method; particle mesh codes

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APA (6^th Edition):

Cunnama, D. (2013). Galaxy Evolution and Cosmology using Supercomputer Simulations by Daniel Cunnama . (Thesis). University of the Western Cape. Retrieved from http://hdl.handle.net/11394/4042

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):

Cunnama, Daniel. “Galaxy Evolution and Cosmology using Supercomputer Simulations by Daniel Cunnama .” 2013. Thesis, University of the Western Cape. Accessed March 06, 2021. http://hdl.handle.net/11394/4042.

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

MLA Handbook (7^th Edition):

Cunnama, Daniel. “Galaxy Evolution and Cosmology using Supercomputer Simulations by Daniel Cunnama .” 2013. Web. 06 Mar 2021.

Vancouver:

Cunnama D. Galaxy Evolution and Cosmology using Supercomputer Simulations by Daniel Cunnama . [Internet] [Thesis]. University of the Western Cape; 2013. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/11394/4042.

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

Council of Science Editors:

Cunnama D. Galaxy Evolution and Cosmology using Supercomputer Simulations by Daniel Cunnama . [Thesis]. University of the Western Cape; 2013. Available from: http://hdl.handle.net/11394/4042

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

Michigan Technological University

28. Mamun, Mohammad Mohiuddin. Non-invasive method to predict viscosity and size using total internal reflection fluorescence microscopy (TIRFM) system.

Degree: MS, Department of Mechanical Engineering-Engineering Mechanics, 2013, Michigan Technological University

URL: https://digitalcommons.mtu.edu/etd-restricted/167

► This study develops an automated analysis tool by combining total internal reflection fluorescence microscopy (TIRFM), an evanescent wave microscopic imaging technique to capture time-sequential… (more)

Subjects/Keywords: Hindered Brownian diffusion; Non-invasive method; Particle tracking; TIRFM; Mechanical Engineering

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APA (6^th Edition):

Mamun, M. M. (2013). Non-invasive method to predict viscosity and size using total internal reflection fluorescence microscopy (TIRFM) system. (Masters Thesis). Michigan Technological University. Retrieved from https://digitalcommons.mtu.edu/etd-restricted/167

Chicago Manual of Style (16^th Edition):

Mamun, Mohammad Mohiuddin. “Non-invasive method to predict viscosity and size using total internal reflection fluorescence microscopy (TIRFM) system.” 2013. Masters Thesis, Michigan Technological University. Accessed March 06, 2021. https://digitalcommons.mtu.edu/etd-restricted/167.

MLA Handbook (7^th Edition):

Mamun, Mohammad Mohiuddin. “Non-invasive method to predict viscosity and size using total internal reflection fluorescence microscopy (TIRFM) system.” 2013. Web. 06 Mar 2021.

Vancouver:

Mamun MM. Non-invasive method to predict viscosity and size using total internal reflection fluorescence microscopy (TIRFM) system. [Internet] [Masters thesis]. Michigan Technological University; 2013. [cited 2021 Mar 06]. Available from: https://digitalcommons.mtu.edu/etd-restricted/167.

Council of Science Editors:

Mamun MM. Non-invasive method to predict viscosity and size using total internal reflection fluorescence microscopy (TIRFM) system. [Masters Thesis]. Michigan Technological University; 2013. Available from: https://digitalcommons.mtu.edu/etd-restricted/167

University of Melbourne

29. Ladiges, Daniel Rowan. Oscillatory rarefied flows: Monte Carlo and variational methods.

Degree: 2016, University of Melbourne

URL: http://hdl.handle.net/11343/108741

► Recent advances in nano-fabrication techniques have led to a proliferation of new devices for a range of applications, including molecular scale mass measurement, atomic scale… (more)

▼ Recent advances in nano-fabrication techniques have led to a proliferation of new devices for a range of applications, including molecular scale mass measurement, atomic scale imaging, and environmental sensing. These devices are often designed to operate at resonance in ambient conditions, where they generate oscillatory flows in the surrounding gas. The ability to model these flows is therefore critical for proper device design and measurement interpretation. Due to their small size, which may be comparable to the mean free path of the gas, nanoscale devices generate low Mach number flows which are inherently rarefied in nature. Rarefied gas flows are typically modelled using the Boltzmann equation, which is analytically intractable in all but the simplest cases. In order to solve the Boltzmann equation in physically realistic situations, numerical techniques are generally required. In this thesis, we propose several new numerical methods for efficiently solving the Boltzmann equation for low Mach number, oscillatory flows, of the type generated by nanoscale devices. First, we propose a new Monte Carlo method which operates in the frequency-domain. This contrasts with existing Monte Carlo methods, which operate exclusively in the time-domain, and simulate oscillatory flows via time dependent sinusoidal boundary conditions or driving forces. The new frequency-domain method is derived for both weight based and deviational Monte Carlo approaches, using a `virtual-time' variable to maintain the inherent time marching nature of these techniques. Both BGK and hard sphere collision models are demonstrated using several canonical flows. In order to compare the computational performance of the existing time and new frequency-domain Monte Carlo methods, we formulate a statistical theory that describes their relative convergence properties. The resulting formulas show that frequency-domain Monte Carlo methods offer a significant improvement in statistical convergence, compared to corresponding time-domain techniques. This finding is confirmed by comparison to simulation data. We then illustrate how the frequency-domain approach may be applied to oscillatory flows of arbitrary time dependence, via an efficient parallelisation technique. In addition to these Monte Carlo approaches, we formulate a new method for obtaining spectral solutions to the frequency-domain Boltzmann equation, via a variational approach. This is achieved by generalising an existing method for approximate solutions of steady flow problems. We then discuss several choices of the required basis functions for spectral methods, which improve convergence for solutions of the frequency-domain Boltzmann equation at moderate to high rarefaction. These are demonstrated using the BGK collision model, for several canonical flows.

Subjects/Keywords: Boltzmann equation; DSMC; numerical solution; particle method; frequency-domain Monte Carlo

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

APA (6^th Edition):

Ladiges, D. R. (2016). Oscillatory rarefied flows: Monte Carlo and variational methods. (Doctoral Dissertation). University of Melbourne. Retrieved from http://hdl.handle.net/11343/108741

Chicago Manual of Style (16^th Edition):

Ladiges, Daniel Rowan. “Oscillatory rarefied flows: Monte Carlo and variational methods.” 2016. Doctoral Dissertation, University of Melbourne. Accessed March 06, 2021. http://hdl.handle.net/11343/108741.

MLA Handbook (7^th Edition):

Ladiges, Daniel Rowan. “Oscillatory rarefied flows: Monte Carlo and variational methods.” 2016. Web. 06 Mar 2021.

Vancouver:

Ladiges DR. Oscillatory rarefied flows: Monte Carlo and variational methods. [Internet] [Doctoral dissertation]. University of Melbourne; 2016. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/11343/108741.

Council of Science Editors:

Ladiges DR. Oscillatory rarefied flows: Monte Carlo and variational methods. [Doctoral Dissertation]. University of Melbourne; 2016. Available from: http://hdl.handle.net/11343/108741

30. Krybus David. Numerical modeling of fluid-structure interaction .

Degree: 2014, Czech University of Technology

URL: http://hdl.handle.net/10467/30663

► A coupled fluid-structure interaction (FSI) analysis represents a challenging task from engineering point of view. Except a few special FSI problems, the only way to… (more)

▼ A coupled fluid-structure interaction (FSI) analysis represents a challenging task from engineering point of view. Except a few special FSI problems, the only way to perform interaction analysis is the use of experimental or numerical methods. This thesis deals with the numerical modeling of fluid-structure interaction adopting so-called staggered approach, which solves both phases separately and employs information exchange on the interface to enforce compatibility. The main objectives of this work are the formulation and development of a numerical model for the analysis of FSI problems, its implementation and validation on benchmark examples. The fluid flow is modeled by the finite element method using Lagrangian formulation of governing equations. This approach is based on the particle finite element method. The computational domain is discretized by abstract particles, for which the incompressible Navier-Stokes equations are solved in each time step, resulting in velocities and pressure values. Lagrangian approach requires frequent remeshing to avoid distortion of background elements defined by topology of particles. For these purposes, a mesh generator based on the Delaunay triangulation is implemented. The boundary of the domain is recovered by the Alpha Shape concept. The developed model of fluid flow is validated on the examples of the water column collapse and free oscillation of a liquid in a container. The coupling of the fluid and structural problems is enabled by the implementation of iterative solver using the Dirichlet-Neumann approach based on the exchange of velocity and pressure values on the interface. Capabilities of the pilot implementation are illustrated on an example of clamped elastic gate of a fluid container.; A coupled fluid-structure interaction (FSI) analysis represents a challenging task from engineering point of view. Except a few special FSI problems, the only way to perform interaction analysis is the use of experimental or numerical methods. This thesis deals with the numerical modeling of fluid-structure interaction adopting so-called staggered approach, which solves both phases separately and employs information exchange on the interface to enforce compatibility. The main objectives of this work are the formulation and development of a numerical model for the analysis of FSI problems, its implementation and validation on benchmark examples. The fluid flow is modeled by the finite element method using Lagrangian formulation of governing equations. This approach is based on the particle finite element method. The computational domain is discretized by abstract particles, for which the incompressible Navier-Stokes equations are solved in each time step, resulting in velocities and pressure values. Lagrangian approach requires frequent remeshing to avoid distortion of background elements defined by topology of particles. For these purposes, a mesh generator based on the Delaunay triangulation is implemented. The boundary of the domain is recovered by the Alpha Shape concept. The… Advisors/Committee Members: Patzák Bořek (advisor).

Subjects/Keywords: Particle finite element method; Fluid-structure interaction; Numerical methods

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

APA (6^th Edition):

David, K. (2014). Numerical modeling of fluid-structure interaction . (Thesis). Czech University of Technology. Retrieved from http://hdl.handle.net/10467/30663

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):

David, Krybus. “Numerical modeling of fluid-structure interaction .” 2014. Thesis, Czech University of Technology. Accessed March 06, 2021. http://hdl.handle.net/10467/30663.

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

MLA Handbook (7^th Edition):

David, Krybus. “Numerical modeling of fluid-structure interaction .” 2014. Web. 06 Mar 2021.

Vancouver:

David K. Numerical modeling of fluid-structure interaction . [Internet] [Thesis]. Czech University of Technology; 2014. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/10467/30663.

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

Council of Science Editors:

David K. Numerical modeling of fluid-structure interaction . [Thesis]. Czech University of Technology; 2014. Available from: http://hdl.handle.net/10467/30663

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

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Open Access Theses and Dissertations