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Delft University of Technology
1.
Vargas Jimenez, J.A. (author).
Development of a Wave Drag Prediction Tool for the Conceptual Design Phase.
Degree: 2015, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:fadcbb6a-67f8-419b-9e4f-a546866c738a 
► The goal of this thesis is to improve the wave drag estimation techniques in the aircraft conceptual design. Based on the most relevant methods, among…
(more)
▼ The goal of this thesis is to improve the wave drag estimation techniques in the aircraft conceptual design. Based on the most relevant methods, among those developed in the past 60 years, three methods are proposed as an attempt to include more design variables and improve the accuracy of the wave drag prediction. The proposed methods include the use of supercritical airfoils and the cross sectional area distribution of the aircraft as port of the wave drag estimation. The proposed methods are compared to experimental drag data, available in the literature, of four high-subsonic conventional transport aircraft. An accuracy analysis is performed evaluating how well each method predicts the drag divergence Mach number, the wave drag at Mach number 0.8, and how well the predicted curve fitted with the experimental data. The analysis led to the conclusion that the results of the Delta method shows better agreement with the experimental data than the proposed methods. The state of the art techniques and the proposed methods have been implemented and integrated into a conceptual design tool, as a new module. The module functionality, including its settings, inputs, outputs and functions are also described in this document.
Flight performance and propulsion
Flight performance and propulsion
Aerospace Engineering
Advisors/Committee Members: Vos, R. (mentor).
Subjects/Keywords: wave drag
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APA (6th Edition):
Vargas Jimenez, J. A. (. (2015). Development of a Wave Drag Prediction Tool for the Conceptual Design Phase. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:fadcbb6a-67f8-419b-9e4f-a546866c738a
Chicago Manual of Style (16th Edition):
Vargas Jimenez, J A (author). “Development of a Wave Drag Prediction Tool for the Conceptual Design Phase.” 2015. Masters Thesis, Delft University of Technology. Accessed January 24, 2021.
http://resolver.tudelft.nl/uuid:fadcbb6a-67f8-419b-9e4f-a546866c738a.
MLA Handbook (7th Edition):
Vargas Jimenez, J A (author). “Development of a Wave Drag Prediction Tool for the Conceptual Design Phase.” 2015. Web. 24 Jan 2021.
Vancouver:
Vargas Jimenez JA(. Development of a Wave Drag Prediction Tool for the Conceptual Design Phase. [Internet] [Masters thesis]. Delft University of Technology; 2015. [cited 2021 Jan 24].
Available from: http://resolver.tudelft.nl/uuid:fadcbb6a-67f8-419b-9e4f-a546866c738a.
Council of Science Editors:
Vargas Jimenez JA(. Development of a Wave Drag Prediction Tool for the Conceptual Design Phase. [Masters Thesis]. Delft University of Technology; 2015. Available from: http://resolver.tudelft.nl/uuid:fadcbb6a-67f8-419b-9e4f-a546866c738a
Delft University of Technology
2.
Veldhuizen, R. (author).
Development of a fast aerodynamic tool using meta-modeling techniques.
Degree: 2015, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:8741189f-1006-4e79-89d8-8c7bc11d6baa
► There is a need for a wave drag method that combines the speed of handbook methods with the accuracy of computational methods. Especially determining the…
(more)
▼ There is a need for a wave drag method that combines the speed of handbook methods with the accuracy of computational methods. Especially determining the onset of wave drag as well as the initial drag rise is important in initial design stages. Meta-models allow this by capturing the trends present in previously computed data, providing an accurate and fast representation. In this report, it is investigated what gains can be achieved by applying the meta-modeling method GT-Approx to the aerodynamic tool MSES. The total drag calculated by MSES for a super critical airfoil was verified using wind tunnel experiments. It was found that aerodynamic characteristics and pressure distributions are accurate up until M = 0.76. GT-Approx was critically evaluated. It was found that the general prediction quality was good, but that the error increased substantially for complex cases, such as high M or high cl This issue is solved by increasing the resolution of the input data. By optimizing the resolution for the different input variables the average prediction error decreased by 30% for cdv and 70% for cdw. Especially for the difficult cases, the accuracy greatly improved. Two A320 variants are evaluated using GT-Approx and a direct application of MSES. The performance of GTApprox is good. An average difference of 0.21 drag counts between MSES and GT-Approx was achieved, with an in-calculation computation time of 5.13?10??s per calculation instead of 5.58s using a direct application of MSES. GT-Approx is extended to a quasi-3Dmethod, using the simple sweep method. This quasi-3D method is used to calculate the value of CDw for two test cases. The calculated values of CDw are compared with CFD data. It was found that the region of validity of the quasi-3D method is highly limited. Up until 60% of the wing, root and tip effects, fuselage effects and engine installation effects render any comparison useless. Beyond this value the first test case showed no correlation, whereas the second showed reasonable accuracy. Due to lack of more 3D CFD data, no clear explanation for the difference was found. In general it is concluded that the combination of an aerodynamic tool with a meta-model is able to combine low computation times with high accuracy, but only if the aerodynamic model is accurate.
Flight Performance & Propulsion
Aerospace Engineering
Advisors/Committee Members: Vos, R. (mentor).
Subjects/Keywords: wave drag; meta-modeling
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APA (6th Edition):
Veldhuizen, R. (. (2015). Development of a fast aerodynamic tool using meta-modeling techniques. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:8741189f-1006-4e79-89d8-8c7bc11d6baa
Chicago Manual of Style (16th Edition):
Veldhuizen, R (author). “Development of a fast aerodynamic tool using meta-modeling techniques.” 2015. Masters Thesis, Delft University of Technology. Accessed January 24, 2021.
http://resolver.tudelft.nl/uuid:8741189f-1006-4e79-89d8-8c7bc11d6baa.
MLA Handbook (7th Edition):
Veldhuizen, R (author). “Development of a fast aerodynamic tool using meta-modeling techniques.” 2015. Web. 24 Jan 2021.
Vancouver:
Veldhuizen R(. Development of a fast aerodynamic tool using meta-modeling techniques. [Internet] [Masters thesis]. Delft University of Technology; 2015. [cited 2021 Jan 24].
Available from: http://resolver.tudelft.nl/uuid:8741189f-1006-4e79-89d8-8c7bc11d6baa.
Council of Science Editors:
Veldhuizen R(. Development of a fast aerodynamic tool using meta-modeling techniques. [Masters Thesis]. Delft University of Technology; 2015. Available from: http://resolver.tudelft.nl/uuid:8741189f-1006-4e79-89d8-8c7bc11d6baa
Delft University of Technology
3.
Ni, Y. (author).
Drag forces on vegetation due to waves and currents.
Degree: 2014, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:0f6ee54a-098d-4fe7-b298-04ae64459acd
► Vegetation in coastal areas plays an important role in its environment. In addition, vegetation can also be utilized for coastal protection. Incoming wave energy could…
(more)
▼ Vegetation in coastal areas plays an important role in its environment. In addition, vegetation can also be utilized for coastal protection. Incoming
wave energy could be effectively attenuated by the upstanding vegetation plants. The reduced
wave energy results in stabilized seabed and harmonious environment in coastal zones. Nowadays, an increasing number of projects have been carried out to apply vegetation as a soft measure for coastal protection.
Wave energy dissipation by vegetation is primarily induced by the work done by
drag force acting on the vegetation. A
drag coefficient (CD) is introduced to characterize the flow resistance from the plant stems. Knowledge of CD is of great importance for understanding and predicting the
wave dissipation process. In previous studies, relations between CD and Reynolds number (Re) have been proposed in pure current or pure
wave. In addition, relations between CD and the Keulegan-Carpenter number (abbreviated as KC and KC=Uw*Tw/d, Tw is the
wave period and d is the plant stem diameter) have also been suggested. In Keulegan-Carptenter number, the
wave period Tw is also considered. Since waves are oscillatory flow, it would be preferable to use the KC number to describe the behaviour of CD in
wave-present conditions. However, contradictory conclusions are found in the literature on the CD-KC relation in pure
wave condition. Monotonous decreasing of CD with KC has been reported for multiple vegetation mimics. On the contrary, the rise-and-fall variation trend has been observed in pure
wave, but only for single cylinder. It is noted that the transition point (from rise to fall) occurs when KC value is small, which is often left out in the experiment with multiple vegetation mimics in previous studies. Hence, it is necessary to investigate the variation trend of CD-KC for multiple vegetation mimics in pure
wave with a wider KC range. Moreover, background tidal currents may also play a role in the
wave dissipation process. It is often the case that when the tide penetrates the coastal wetlands during flooding phase, waves propagate in the same direction as the tidal currents. The underlying current may affect the behaviour of oscillatory
wave flow during the energy-damping process and the CD-KC relation. Yet, the CD-KC relation in combined current-
wave flow has not been reported in previous studies. In order to fill the knowledge gap in the CD-KC relation, an experimental approach was adopted by using the laboratory flume to replicate such complicated hydrodynamics. The flume is 40m long and 0.8m wide, with a patch of rigid wooden cylinders as vegetation mimics installed over the entire channel width over a 6m long test section. Pure
wave can be generated by the
wave generator. The underlying current can be made by using a water circulation system in the flume. After the generation of underlying current, waves could be generated afterwards and propagate together with the underlying current in the flume. The velocity was measured using EMS within the vegetation patch. Direct…
Advisors/Committee Members: Uijttewaal, W.S.J. (mentor), Zitman, T.J. (mentor), Hu, Z. (mentor).
Subjects/Keywords: vegetation; drag; Keulegan-Carpenter number; wave; combined current-wave flow
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APA (6th Edition):
Ni, Y. (. (2014). Drag forces on vegetation due to waves and currents. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:0f6ee54a-098d-4fe7-b298-04ae64459acd
Chicago Manual of Style (16th Edition):
Ni, Y (author). “Drag forces on vegetation due to waves and currents.” 2014. Masters Thesis, Delft University of Technology. Accessed January 24, 2021.
http://resolver.tudelft.nl/uuid:0f6ee54a-098d-4fe7-b298-04ae64459acd.
MLA Handbook (7th Edition):
Ni, Y (author). “Drag forces on vegetation due to waves and currents.” 2014. Web. 24 Jan 2021.
Vancouver:
Ni Y(. Drag forces on vegetation due to waves and currents. [Internet] [Masters thesis]. Delft University of Technology; 2014. [cited 2021 Jan 24].
Available from: http://resolver.tudelft.nl/uuid:0f6ee54a-098d-4fe7-b298-04ae64459acd.
Council of Science Editors:
Ni Y(. Drag forces on vegetation due to waves and currents. [Masters Thesis]. Delft University of Technology; 2014. Available from: http://resolver.tudelft.nl/uuid:0f6ee54a-098d-4fe7-b298-04ae64459acd
Texas A&M University
4.
Anderson, Mary Elizabeth.
Measurements and Linear Wave Theory Based Simulations of Vegetated Wave Hydrodynamics for Practical Applications.
Degree: MS, Ocean Engineering, 2011, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2010-08-8348
► Wave attenuation by vegetation is a highly dynamic process and its quantification is important for accurately understanding and predicting coastal hydrodynamics. However, the influence of…
(more)
▼ Wave attenuation by vegetation is a highly dynamic process and its quantification is important for accurately understanding and predicting coastal hydrodynamics. However, the influence of vegetation on
wave dissipation is not yet fully established nor implemented in current hydrodynamic models. A series of laboratory experiments were conducted at the Haynes Coastal Engineering Laboratory and in a two-dimensional flume at Texas A and M University to investigate the influence of relative vegetation height, stem density, and stem spacing uniformity on
wave attenuation. Vegetation fields were represented as random cylinder arrays where the stem density and spatial variation were based on collected field specimens. Experimental results indicate
wave attenuation is dependent on relative vegetation height, stem density, and stem spacing standard deviation. As stems occupy more of the water column, an increase in attenuation occurred given that the highest
wave particle velocities are being impeded. Sparse vegetation fields dissipated less
wave energy than the intermediate density; however, the extremely dense fields dissipated very little, if any,
wave energy and sometimes
wave growth was observed. This is possibly due to the highest density exceeding some threshold where maximum
wave attenuation capabilities are exceeded and lowering of damping ensues. Additionally,
wave attenuation increased with higher stem spatial variation due to less wake sheltering. A one-dimensional model with an analytical vegetation dissipation term was developed and calibrated to these experimental results to capture the
wave transformation over the vegetation beds and to investigate the behavior of the vegetation field bulk
drag coefficient. The best fit between predicted and measured
wave heights was obtained using the least squares method considering the bulk
drag coefficient as the single calibration parameter. The model was able to realistically capture the
wave transformations over vegetation. Upon inspection, the bulk
drag coefficient shared many of the dependencies of the total
wave dissipation. The bulk
drag coefficient increased with larger relative vegetation heights as well as with higher stem spacing standard deviation. Higher densities resulted in a lowering of the bulk
drag coefficient but generally an increase in
wave attenuation. These parameters and their influences help in identifying the important parameters for numerical studies to further our understanding of
wave attenuation by wetlands.
Advisors/Committee Members: Irish, Jennifer L. (advisor), McKee Smith, Jane (committee member), Kaihatu, James (committee member), Thornton, Daniel (committee member).
Subjects/Keywords: wave attenuation; vegetation dissipation; wetlands; vegetation bulk drag coefficient
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APA (6th Edition):
Anderson, M. E. (2011). Measurements and Linear Wave Theory Based Simulations of Vegetated Wave Hydrodynamics for Practical Applications. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2010-08-8348
Chicago Manual of Style (16th Edition):
Anderson, Mary Elizabeth. “Measurements and Linear Wave Theory Based Simulations of Vegetated Wave Hydrodynamics for Practical Applications.” 2011. Masters Thesis, Texas A&M University. Accessed January 24, 2021.
http://hdl.handle.net/1969.1/ETD-TAMU-2010-08-8348.
MLA Handbook (7th Edition):
Anderson, Mary Elizabeth. “Measurements and Linear Wave Theory Based Simulations of Vegetated Wave Hydrodynamics for Practical Applications.” 2011. Web. 24 Jan 2021.
Vancouver:
Anderson ME. Measurements and Linear Wave Theory Based Simulations of Vegetated Wave Hydrodynamics for Practical Applications. [Internet] [Masters thesis]. Texas A&M University; 2011. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-08-8348.
Council of Science Editors:
Anderson ME. Measurements and Linear Wave Theory Based Simulations of Vegetated Wave Hydrodynamics for Practical Applications. [Masters Thesis]. Texas A&M University; 2011. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-08-8348
Delft University of Technology
5.
Kinderman, Hendrik Wisse (author).
The impact of vertical wing placement on the wave drag and sonic-boom performance at supersonic speeds.
Degree: 2017, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:b5eaa808-6067-46a5-8d45-0e14d18ceeef
► This research project aims at obtaining a better understanding of vertically translating the wing and the related wing-body interference effects on the drag and sonic…
(more)
▼ This research project aims at obtaining a better understanding of vertically translating the wing and the related wing-body interference effects on the
drag and sonic boom. Computational Fluid Dynamics (CFD) analysis using the Euler equations has been used to evaluate an airplane with different vertical wing placements at a lift coefficient of 0.15 at a Mach-number of 1.6 and also in zero-lift conditions. Pressure distributions,
drag forces and pressure signatures have been calculated in order to assess the performance in terms of
wave drag and sonic booms. These results have been analysed to find out why certain effects are happening for these configurations. The low wing configuration has the highest lift-to-
drag ratio due to interference on the upper wing surface close to the fuselage. The lift-to-
drag ratio for CL = 0.15 is found to be 4.79% higher compared to the worst performing configuration, the high wing configuration. Due to the local geometry of the low wing configuration it is possible to cre- ate additional suction on the upper wing surface, which positively affects the performance. Pressure signatures are extracted at 1 body-length distance (70푚) from the aircraft for several azimuth angles. These distributions show that the low wing configuration also has the lowest impulse and maximum overpressure. The higher wing configurations show an extra peak in overpressure emanating from the trailing end of the wing, which is created due to interference effects. Below the wing surface there is a large volume of the fuselage, while it is absent for the low wing configuration. Therefore the higher wing configurations show an extra peak in the pressure signature. Next to this discovery, an analysis is presented to relate the geometry of the configurations to the
wave drag by assessing the cross-sectional area distribution using different intersection methods. These methods are compared with other methods found in the literature. Two methods which use a single Mach-cone have been analysed, as well as a method incorporating a forward and a backward pointed Mach-cone. One method translates a Mach-cone vertically to align the vertex of the Mach-cone with the centroid of the intersection with the aircraft. This gives an x,z-position which can be used to adjust the area distribution. The
drag for the methods using a single Mach-cone was overestimated by a factor of 2, but after multiplying these results by a factor of / the results for the heigh-weighted Mach-cone method approached the
wave drag results from CFD within 5%. The double Mach-cone method showed an even better agreement with less variation, while no multiplication factor was applied. A further analysis has taken place to find out why some methods that incorporate a single Mach- cone to evaluate the cross-sectional area to calculate the
wave drag, overestimate the
drag by a factor of 2. It is found that these methods do not overestimate the
drag for a simple shape, such as a Sears- Haack body. The methods simply overestimate the cross-sectional area,…
Advisors/Committee Members: Schrijer, Ferdinand (mentor), Delft University of Technology (degree granting institution).
Subjects/Keywords: sonic boom; vertical wing placement; wave drag; drag; supersonic; pressure signature; lift; zero-lift; area ruling; area rule; Mach; cone
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APA (6th Edition):
Kinderman, H. W. (. (2017). The impact of vertical wing placement on the wave drag and sonic-boom performance at supersonic speeds. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:b5eaa808-6067-46a5-8d45-0e14d18ceeef
Chicago Manual of Style (16th Edition):
Kinderman, Hendrik Wisse (author). “The impact of vertical wing placement on the wave drag and sonic-boom performance at supersonic speeds.” 2017. Masters Thesis, Delft University of Technology. Accessed January 24, 2021.
http://resolver.tudelft.nl/uuid:b5eaa808-6067-46a5-8d45-0e14d18ceeef.
MLA Handbook (7th Edition):
Kinderman, Hendrik Wisse (author). “The impact of vertical wing placement on the wave drag and sonic-boom performance at supersonic speeds.” 2017. Web. 24 Jan 2021.
Vancouver:
Kinderman HW(. The impact of vertical wing placement on the wave drag and sonic-boom performance at supersonic speeds. [Internet] [Masters thesis]. Delft University of Technology; 2017. [cited 2021 Jan 24].
Available from: http://resolver.tudelft.nl/uuid:b5eaa808-6067-46a5-8d45-0e14d18ceeef.
Council of Science Editors:
Kinderman HW(. The impact of vertical wing placement on the wave drag and sonic-boom performance at supersonic speeds. [Masters Thesis]. Delft University of Technology; 2017. Available from: http://resolver.tudelft.nl/uuid:b5eaa808-6067-46a5-8d45-0e14d18ceeef
York University
6.
Majdzadeh, Mahtab.
Gravity Wave Generation and Momentum Deposition in the Atmosphere.
Degree: PhD, Earth & Space Science, 2018, York University
URL: http://hdl.handle.net/10315/34323
► The first part of this study investigates gravity wave parameterization in the middle atmosphere, focusing on internal waves with a broad spectrum of phase speeds.…
(more)
▼ The first part of this study investigates gravity
wave parameterization in the middle atmosphere, focusing on internal waves with a broad spectrum of phase speeds. A column model based on CIRA wind and temperature profiles is employed to assess the characteristics of the Hines Doppler-Spread (1997) and Warner-McIntyre-Scinocca (2001) nonorographic
drag parameterizations for internal gravity waves. The Alexander-Dunkerton (1999) variant of Warner-McIntyre-Scinocca scheme is also briefly considered.
This study goes into more detail than previous comparisons by performing a spectral analysis of the momentum deposition and
drag, and by examining the ability of each scheme to reproduce saturation. Comparisons with pure critical level filtering are also made, and it is found that Hines DSP mainly constitutes an enhancement to critical level absorption, while the Warner-McIntyre-Scinocca scheme produces substantially different
wave drag profiles. We find several undesirable characteristics in the
drag produced by the Hines scheme. For typical midlatitude profiles, it produces an abrupt onset of large accelerations that are confined to a relatively narrow layer. It is also unable to reproduce
wave spectra consistent with observed saturation at high vertical wavenumbers.
The second part of this study investigates the generation mechanisms of the gravity waves over Newfoundland and Labrador (NL). We performed a series of simulations for a selection of the strongest peak events using WRF model to further investigate the characteristics and generation mechanisms of gravity
wave peak events over NL. We studied three different peak events, 2003, 2008 and 2014.
We showed that gravity
wave events in the winter hotspot region over NL can have both topographic and jet streak sources. In the cases we examined, one source of waves was the Torngat range on the northern coast of Labrador. However, the other two
wave sources were in fact outside the hotspot region, and a combination of advection and propagation caused those packets to enter the hotspot in the middle atmosphere. We have demonstrated that topographic
wave packets, which are normally assumed to remain stationary over the source, can in fact be advected far downstream from the source.
Advisors/Committee Members: Klaassen, Gary (advisor), Chen, Yongsheng (advisor).
Subjects/Keywords: Atmospheric sciences; Gravity Waves; Gravity Wave Drag Parameterization; Momentum Deposition; Middle Atmosphere; Gravity Wave Hotspots; Gravity Wave Generation Mechanisms; Numerical Weather Prediction; Weather Research and Forecasting
Model
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APA (6th Edition):
Majdzadeh, M. (2018). Gravity Wave Generation and Momentum Deposition in the Atmosphere. (Doctoral Dissertation). York University. Retrieved from http://hdl.handle.net/10315/34323
Chicago Manual of Style (16th Edition):
Majdzadeh, Mahtab. “Gravity Wave Generation and Momentum Deposition in the Atmosphere.” 2018. Doctoral Dissertation, York University. Accessed January 24, 2021.
http://hdl.handle.net/10315/34323.
MLA Handbook (7th Edition):
Majdzadeh, Mahtab. “Gravity Wave Generation and Momentum Deposition in the Atmosphere.” 2018. Web. 24 Jan 2021.
Vancouver:
Majdzadeh M. Gravity Wave Generation and Momentum Deposition in the Atmosphere. [Internet] [Doctoral dissertation]. York University; 2018. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/10315/34323.
Council of Science Editors:
Majdzadeh M. Gravity Wave Generation and Momentum Deposition in the Atmosphere. [Doctoral Dissertation]. York University; 2018. Available from: http://hdl.handle.net/10315/34323
Delft University of Technology
7.
Haage, Samantha (author).
Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission.
Degree: 2018, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:c0e2b22d-466e-4879-805a-4fdb81393e7c
► Due to the removal of mangrove forests, coastal zones can suffer from severe erosion. One of the proposed solutions is the construction of permeable structures.…
(more)
▼ Due to the removal of mangrove forests, coastal zones can suffer from severe erosion. One of the proposed solutions is the construction of permeable structures. This study aims to optimise the design of permeable (brushwood) structures in order to restore the sediment balance and encourage mangrove re-establishment on tropical mud coasts. Preferably
wave transmission should be low in order to create a calmer climate behind the structure. In that way sediment is able to settle down, which could lead to a recovery of the mud profile. It is also preferred that reflection by the structure is low. High reflection rates cause scour holes that lead to instability of the structure. Furthermore, scour holes could hinder future mangrove re-establishment. Aiming to achieve low reflection and transmission rates, the dissipation inside the structure has to be as high as possible. Experiments were conducted in the 40 meter
wave flume at the Environmental Fluid Mechanics Laboratory at TU Delft. The permeable structure was schematized as an array of cylinders. With the physical scale model various effects could be tested, including the porosity, structure width, arrangement, orientation, etc. The tests were done for 5 different
wave cases, from which the
wave energy distribution over reflection, dissipation and transmission was determined. The existing brushwood structures require intensive maintenance. This is partly due to the sinking of the material into the soft mud. Also, the brushwood material washes away often as it is lighter than water and difficult to constrain in vertical direction. An alternative design that requires less maintenance would be preferred. Therefore, it was interesting to see whether a comparable amount of
wave dissipation could be achieved by using vertical elements only. One important finding is that in more shallow water regions, vertical and horizontal orientations have similar dissipation rates. In water regions that go more towards deep water, the horizontal structures have higher dissipation rates. This can be explained by the relative importance of the horizontal and vertical velocities due to the
wave motion. In deep water vertical velocities are relatively high. As the horizontal elements have more exposure to this component in comparison to the vertical elements, they provide more dissipation. In shallow water the relative importance of the vertical velocities is lower, which explains the similar dissipation rates of the two orientations. The analytical model of Dalrymple (1984) was used to describe the energy dissipation through the structures.
Drag coefficients were derived by using the calibration method. For KC<15 the
drag coefficients start increasing. This is possibly due to the relative importance of the inertia force. Comparing the
drag coefficients to the ones derived from direct force and velocity measurements in previous studies showed relative high values. This could be due to an underestimation of the horizontal velocity due to the
wave motion. The velocity that is used is the…
Advisors/Committee Members: Gijón Mancheño, Alejandra (mentor), Sirks, Emma (mentor), Uijttewaal, Wim (graduation committee), Kuiper, Coen (graduation committee), Hofland, Bas (graduation committee), Winterwerp, Han (graduation committee), Delft University of Technology (degree granting institution).
Subjects/Keywords: Building with Nature; Brushwood structures; Demak; Indonesia; BioManCo; Mangroves; Wave flume experiments; Permeable Structures; Physical scale model; Wave dissipation; Cylinders; Drag coefficients; Arrays of Cylinders; Wave Energy Balance; Dalrymple
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APA (6th Edition):
Haage, S. (. (2018). Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:c0e2b22d-466e-4879-805a-4fdb81393e7c
Chicago Manual of Style (16th Edition):
Haage, Samantha (author). “Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission.” 2018. Masters Thesis, Delft University of Technology. Accessed January 24, 2021.
http://resolver.tudelft.nl/uuid:c0e2b22d-466e-4879-805a-4fdb81393e7c.
MLA Handbook (7th Edition):
Haage, Samantha (author). “Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission.” 2018. Web. 24 Jan 2021.
Vancouver:
Haage S(. Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission. [Internet] [Masters thesis]. Delft University of Technology; 2018. [cited 2021 Jan 24].
Available from: http://resolver.tudelft.nl/uuid:c0e2b22d-466e-4879-805a-4fdb81393e7c.
Council of Science Editors:
Haage S(. Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission. [Masters Thesis]. Delft University of Technology; 2018. Available from: http://resolver.tudelft.nl/uuid:c0e2b22d-466e-4879-805a-4fdb81393e7c
Delft University of Technology
8.
Drost, Lisanne (author).
The Submerged Floating Tunnel: An experimental study on the hydrodynamics and kinematics of a submerged rectangular cylinder in a wave-current environment.
Degree: 2019, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:91a1c1bf-474b-4952-9485-c53f2fe353f0
► This study presents the results of small scale flume experiments on a submerged rectangular cylinder subjected to a current, regular wave and combined wave-current environment.…
(more)
▼ This study presents the results of small scale flume experiments on a submerged rectangular cylinder subjected to a current, regular
wave and combined
wave-current environment. The objective of the study is to gain more knowledge about the hydrodynamics around and the kinematics of a submerged structure, to give a contribute to the research field of the submerged floating tunnel. For this study a rectangular cylinder with an aspect ratio (breadth-depth) of 2.5 is used. Two relative submergence depths (flume depth/model submergence) of 2.75 and 1.63 are tested. For all tests a still water depth of 0.7 m is applied. Waves resulting in very low KC numbers of <1 for regular waves and KC[1+U_c/U_m ]<2 for combined waves-current are generated. To create a combined
wave-current environment, a current is created in the flume, to which waves are added by the
wave generator. The water velocity is measured in front of the model. To approximate the water velocity at the model, a time/phase shift is added to the velocity signal. Linear
wave theory is applied to approximate the amplitudes of the orbital velocities at the depth of the model. For the first part of the study, on the hydrodynamic forces, the cylinder is rigidly fixed in the flume. Due to the inertia dominance for low KC numbers, the relationship between the
wave parameters and the hydrodynamic forces is well described by the relationship between the
wave parameters and the water particle accelerations. The vertical hydrodynamic forces are found to be larger than the horizontal hydrodynamic forces. The force coefficients from this study are compared to coefficient found in previous studies. The
drag coefficients for the only current tests agree well with the results from (Courchesne & Laneville, 1979), (Bearman & Trueman, 1972), (Nakaguchi, 1968) and (Venugopal, 2006). For the regular
wave and combined
wave-current conditions comparable results are found to those by Venugopal for a rectangular cylinder towed through a
wave field (Venugopal, 2008). The
drag coefficients in the present study show a similar trend in magnitude as in the study by Venugopal. However, the magnitudes have an opposite sign due to the velocity phase shift method applied in the present study. Nevertheless, the effect of this difference on the total force prediction is insignificant, because of inertia dominance. In general, the Morison equation predicts the measured horizontal force well for regular waves. Adding a current component to the waves results in a larger error between the computed Morison forces and the measured force. However, an increase in the magnitude of the added velocity does not lead to a significant increase of this error. The second part of the study focuses on the same cylinder, only not fixed but held in place by 4 tethers. For these tests a buoyancy to weight ratio of 1.5 is applied. The used tested angles between the tethers and the flume bottom are 30˚ and 70 ̊. The water depth, the
wave types and model submergence depths are remained equal to the first…
Advisors/Committee Members: Uijttewaal, Wim (mentor), Chen, Xuexue (graduation committee), Peters, Dirk Jan (graduation committee), Reinders, Kristina (graduation committee), Delft University of Technology (degree granting institution).
Subjects/Keywords: wave-current interaction; drag forces; intertia forces; rectangle; tether; submerged floating tunnel; Hydrodynamic; Morison's equation; Experimental; force coëfficients; kinematics; displacments; accelerations
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APA (6th Edition):
Drost, L. (. (2019). The Submerged Floating Tunnel: An experimental study on the hydrodynamics and kinematics of a submerged rectangular cylinder in a wave-current environment. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:91a1c1bf-474b-4952-9485-c53f2fe353f0
Chicago Manual of Style (16th Edition):
Drost, Lisanne (author). “The Submerged Floating Tunnel: An experimental study on the hydrodynamics and kinematics of a submerged rectangular cylinder in a wave-current environment.” 2019. Masters Thesis, Delft University of Technology. Accessed January 24, 2021.
http://resolver.tudelft.nl/uuid:91a1c1bf-474b-4952-9485-c53f2fe353f0.
MLA Handbook (7th Edition):
Drost, Lisanne (author). “The Submerged Floating Tunnel: An experimental study on the hydrodynamics and kinematics of a submerged rectangular cylinder in a wave-current environment.” 2019. Web. 24 Jan 2021.
Vancouver:
Drost L(. The Submerged Floating Tunnel: An experimental study on the hydrodynamics and kinematics of a submerged rectangular cylinder in a wave-current environment. [Internet] [Masters thesis]. Delft University of Technology; 2019. [cited 2021 Jan 24].
Available from: http://resolver.tudelft.nl/uuid:91a1c1bf-474b-4952-9485-c53f2fe353f0.
Council of Science Editors:
Drost L(. The Submerged Floating Tunnel: An experimental study on the hydrodynamics and kinematics of a submerged rectangular cylinder in a wave-current environment. [Masters Thesis]. Delft University of Technology; 2019. Available from: http://resolver.tudelft.nl/uuid:91a1c1bf-474b-4952-9485-c53f2fe353f0
University of Kentucky
9.
Calhoun, John C.
LOW REYNOLDS NUMBER FLOW FIELD MODIFICATION VIA TRAVELLING WAVE ACTUATION OF A VERTICALLY ALIGNED WIRE ARRAY SURFACE.
Degree: 2012, University of Kentucky
URL: https://uknowledge.uky.edu/me_etds/19
► Experiments were conducted to observe the effects of an active wire surface on low-Reynolds number Poiseuille flow. The objective was to evaluate the feasibility of…
(more)
▼ Experiments were conducted to observe the effects of an active wire surface on low-Reynolds number Poiseuille flow. The objective was to evaluate the feasibility of actuating piezoelectric nanowires into a travelling wave motion in order to reduce wall shear stress in turbulent flows. Studies have shown that travelling wave motions introduced into the bounding wall of turbulent flow can reduce wall shear stress by disrupting the formation of drag-inducing coherent vortical structures. A Reynolds number scaled flow facility was designed to represent the near-wall region of turbulent flow. A wire surface was installed in the bounding wall and dynamically actuated into a travelling wave. Particle image velocimetry was used to measure the flow. Deviations in the flow were analyzed and a perturbation depth of 5 – 6 wire lengths was observed. Phase averaged flow fields were examined to evaluate the structure of the disturbances introduced into the flow. Non-dimensional analysis of the results indicated that the modifications to the flow depended on Strouhal number and actuation amplitude, but were independent of Reynolds number. The results suggest that the penetration depth of the flow perturbations introduced by an active nanowire surface is sufficient to influence wall shear stress.
Subjects/Keywords: Transverse-wave Flow Control; Wire Array; Drag Reduction; Turbulent Wall-Bounded Flow; Low Reynolds Flow; Aerodynamics and Fluid Mechanics; Mechanical Engineering
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APA (6th Edition):
Calhoun, J. C. (2012). LOW REYNOLDS NUMBER FLOW FIELD MODIFICATION VIA TRAVELLING WAVE ACTUATION OF A VERTICALLY ALIGNED WIRE ARRAY SURFACE. (Masters Thesis). University of Kentucky. Retrieved from https://uknowledge.uky.edu/me_etds/19
Chicago Manual of Style (16th Edition):
Calhoun, John C. “LOW REYNOLDS NUMBER FLOW FIELD MODIFICATION VIA TRAVELLING WAVE ACTUATION OF A VERTICALLY ALIGNED WIRE ARRAY SURFACE.” 2012. Masters Thesis, University of Kentucky. Accessed January 24, 2021.
https://uknowledge.uky.edu/me_etds/19.
MLA Handbook (7th Edition):
Calhoun, John C. “LOW REYNOLDS NUMBER FLOW FIELD MODIFICATION VIA TRAVELLING WAVE ACTUATION OF A VERTICALLY ALIGNED WIRE ARRAY SURFACE.” 2012. Web. 24 Jan 2021.
Vancouver:
Calhoun JC. LOW REYNOLDS NUMBER FLOW FIELD MODIFICATION VIA TRAVELLING WAVE ACTUATION OF A VERTICALLY ALIGNED WIRE ARRAY SURFACE. [Internet] [Masters thesis]. University of Kentucky; 2012. [cited 2021 Jan 24].
Available from: https://uknowledge.uky.edu/me_etds/19.
Council of Science Editors:
Calhoun JC. LOW REYNOLDS NUMBER FLOW FIELD MODIFICATION VIA TRAVELLING WAVE ACTUATION OF A VERTICALLY ALIGNED WIRE ARRAY SURFACE. [Masters Thesis]. University of Kentucky; 2012. Available from: https://uknowledge.uky.edu/me_etds/19
Louisiana State University
10.
Jadhav, Ranjit S.
Field Investigation of Wave and Surge Attenuation in Salt Marsh Vegetation and Wave Climate in a Shallow Estuary.
Degree: PhD, Civil and Environmental Engineering, 2012, Louisiana State University
URL: etd-11152012-094000
;
https://digitalcommons.lsu.edu/gradschool_dissertations/3939
► This research investigates and quantifies the effectiveness of salt marsh vegetation in reducing storm-induced waves and surge, and the potential for wetland erosion due to…
(more)
▼ This research investigates and quantifies the effectiveness of salt marsh vegetation in reducing storm-induced waves and surge, and the potential for wetland erosion due to wave action, using field measurements on the Louisiana coast. To quantify wave attenuation and wave energy dissipation by vegetation (Spartina alterniflora), wave data were measured along a transect using pressure transducers during two tropical storms. Measurements showed that incident waves attenuated exponentially over the vegetation. The linear spatial wave height reduction rate increased from 1.5% to 4% /m as incident wave height decreased. The bulk drag coefficient estimated from the field measurements decreased with increasing Reynolds (Re) and Keulegan-Carpenter (KC) numbers. The vegetation-induced wave energy dissipation did not linearly follow incident energy, and the degree of non-linearity varied with the dominant wave frequency. The estimated drag coefficient is shown to be frequency-dependent and is parameterized by a frequency-dependent velocity attenuation parameter inside the canopy. The spectral drag coefficient predicts the frequency-dependent energy dissipation with better accuracy than the integral coefficient. The probability distribution of zero-crossing wave heights attenuated by vegetation was observed to deviate from the Rayleigh distribution and follow the theoretically derived one-parameter Weibull distribution which depends on local wave conditions only. Empirical relationships are developed to estimate the shape parameter from the local wave parameters. Field data collected during Tropical storm Ida (2009) and Lee (2011) showed that the surge attenuated at different rates in two estuaries of different topography. Surge reduction by vegetation was more effective on a large marsh. To quantify the potential for wave action to cause erosion of coastal wetlands, directional wave measurements were collected over a seven-month period. Marsh retreat rates estimated in the study area, using the wave power calculated from the field measurements are on the same order of magnitude of the recent marsh loss monitoring data. The empirical relationships of vegetation drag coefficient and wave height probability distribution function can be used to improve coastal modeling and to estimate characteristic wave heights for the design of coastal defense structures fronted by large swaths of salt marsh vegetation.
Subjects/Keywords: Random waves; Salt marsh vegetation; Drag coefficient; Velocity attenuation; Wave energy dissipation; Rayleigh distribution; Wind waves; Marsh erosion; Surge attenuation; Wave attenuation; Tropical storm; Probability density function; Weibull distribution; Wave height distribution; Terrebonne Bay; Barrier islands; Swell
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Manager
APA (6th Edition):
Jadhav, R. S. (2012). Field Investigation of Wave and Surge Attenuation in Salt Marsh Vegetation and Wave Climate in a Shallow Estuary. (Doctoral Dissertation). Louisiana State University. Retrieved from etd-11152012-094000 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3939
Chicago Manual of Style (16th Edition):
Jadhav, Ranjit S. “Field Investigation of Wave and Surge Attenuation in Salt Marsh Vegetation and Wave Climate in a Shallow Estuary.” 2012. Doctoral Dissertation, Louisiana State University. Accessed January 24, 2021.
etd-11152012-094000 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3939.
MLA Handbook (7th Edition):
Jadhav, Ranjit S. “Field Investigation of Wave and Surge Attenuation in Salt Marsh Vegetation and Wave Climate in a Shallow Estuary.” 2012. Web. 24 Jan 2021.
Vancouver:
Jadhav RS. Field Investigation of Wave and Surge Attenuation in Salt Marsh Vegetation and Wave Climate in a Shallow Estuary. [Internet] [Doctoral dissertation]. Louisiana State University; 2012. [cited 2021 Jan 24].
Available from: etd-11152012-094000 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3939.
Council of Science Editors:
Jadhav RS. Field Investigation of Wave and Surge Attenuation in Salt Marsh Vegetation and Wave Climate in a Shallow Estuary. [Doctoral Dissertation]. Louisiana State University; 2012. Available from: etd-11152012-094000 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3939
Brno University of Technology
11.
Vondruš, Jan.
Vliv zadní části karoserie na aerodynamickou interakci vozidel: Influence of the rear part of the car body on aerodynamic interaction of vehicles.
Degree: 2020, Brno University of Technology
URL: http://hdl.handle.net/11012/192797
► This diploma thesis is focused on CFD simulation of two platooning DrivAer cars with varying bodyworks. CFD models are made for bodywork variants Estateback, Fastback…
(more)
▼ This diploma thesis is focused on CFD simulation of two platooning DrivAer cars with varying bodyworks. CFD models are made for bodywork variants Estateback, Fastback and Notchback, which are solved by k-epsilon turbulent model. Influence of rear body design on platooning and aerodynamics characteristics is analyzed.
Advisors/Committee Members: Vančura, Jan (advisor), Blaťák, Ondřej (referee).
Subjects/Keywords: DrivAer; Estateback; Fastback; Notchback; úplav; interakce; platooning; odpor; aerodynamický koeficient; CFD; DrivAer; Estateback; Fastback; Notchback; wave; interaction; platooning; drag; aerodynamic coefficient; CFD
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APA (6th Edition):
Vondruš, J. (2020). Vliv zadní části karoserie na aerodynamickou interakci vozidel: Influence of the rear part of the car body on aerodynamic interaction of vehicles. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/192797
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Vondruš, Jan. “Vliv zadní části karoserie na aerodynamickou interakci vozidel: Influence of the rear part of the car body on aerodynamic interaction of vehicles.” 2020. Thesis, Brno University of Technology. Accessed January 24, 2021.
http://hdl.handle.net/11012/192797.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Vondruš, Jan. “Vliv zadní části karoserie na aerodynamickou interakci vozidel: Influence of the rear part of the car body on aerodynamic interaction of vehicles.” 2020. Web. 24 Jan 2021.
Vancouver:
Vondruš J. Vliv zadní části karoserie na aerodynamickou interakci vozidel: Influence of the rear part of the car body on aerodynamic interaction of vehicles. [Internet] [Thesis]. Brno University of Technology; 2020. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/11012/192797.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Vondruš J. Vliv zadní části karoserie na aerodynamickou interakci vozidel: Influence of the rear part of the car body on aerodynamic interaction of vehicles. [Thesis]. Brno University of Technology; 2020. Available from: http://hdl.handle.net/11012/192797
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
George Mason University
12.
Kim, Hyunyul.
Multi-Objective Optimization for Ship Hull Form Design
.
Degree: 2009, George Mason University
URL: http://hdl.handle.net/1920/5620
► Hydrodynamic optimization is an important aspect of ship design. The aim of this dissertation is to develop a computational fluid dynamics (CFD)-based computational tool for…
(more)
▼ Hydrodynamic optimization is an important aspect of ship design. The aim of this dissertation
is to develop a computational fluid dynamics (CFD)-based computational tool for
the hydrodynamic design of ship hull forms. The main components of this hull-form hydrodynamic
optimization tool consist of a hull geometry modeling and modification module, an
optimization module, and a CFD module. This CFD-based multi-objective optimization
tool can automatically modify the shape of a ship hull by minimizing some user-defined
objective functions associated with the hydrodynamic performance of the ship with the aid
of CFD information.
This dissertation covers three main topics. The first topic is the development of a
geometry modeling method to produce the initial hull form and to modify the hull surface
during optimization cycles. Three hull-form modeling methods are developed, which are
NURBS representation, parametric representation, and the combination of the NURBS and
parametric representation to represent a complex geometry and to satisfy different design
requirements. The second topic is the development of various optimization algorithms. Both
single- and multi-objective optimization algorithms are implemented. Several optimization
algorithms are employed and compared with one another in various hull form optimization
applications. Finally, a CFD module is developed to compute the flow field and evaluate
the hydrodynamic performance of the new hull forms obtained during optimization cycles.
A lower-fidelity CFD tool (computer code SSF) and a high-fidelity CFD tool (computer
code FEFLO) are integrated into the CFD module to allow fast evaluation of the objective
functions during design cycles and accurate analysis of the flow about the final optimal hull.
The CFD-based multi-objective optimization tool developed under this dissertation has
been validated and applied in the design of various types of ships. A diverse set of optimal
hull forms can be obtained using the present hydrodynamic optimization tool and significant
improvement in hydrodynamic performance can be achieved.
Subjects/Keywords: optimization algorithms;
hull form optimization;
multi objective;
CFD;
surface modification;
wave drag reduction
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APA (6th Edition):
Kim, H. (2009). Multi-Objective Optimization for Ship Hull Form Design
. (Thesis). George Mason University. Retrieved from http://hdl.handle.net/1920/5620
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Kim, Hyunyul. “Multi-Objective Optimization for Ship Hull Form Design
.” 2009. Thesis, George Mason University. Accessed January 24, 2021.
http://hdl.handle.net/1920/5620.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Kim, Hyunyul. “Multi-Objective Optimization for Ship Hull Form Design
.” 2009. Web. 24 Jan 2021.
Vancouver:
Kim H. Multi-Objective Optimization for Ship Hull Form Design
. [Internet] [Thesis]. George Mason University; 2009. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/1920/5620.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Kim H. Multi-Objective Optimization for Ship Hull Form Design
. [Thesis]. George Mason University; 2009. Available from: http://hdl.handle.net/1920/5620
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Delft University of Technology
13.
Jansen, Wiljan (author).
Wave dissipation in a permeable structure: Experimental research on the physical processes causing energy dissipation inside an array of cylinders.
Degree: 2019, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:acce330d-968a-46a7-853f-73137b06002a
► Mangrove forests, which serve as a natural sea defence, have been degraded by human action during the last decades. To protect and recover these areas,…
(more)
▼ Mangrove forests, which serve as a natural sea defence, have been degraded by human action during the last decades. To protect and recover these areas, different types of permeable structures consisting of bamboo have been proposed and applied. However, these structures are currently based on engineering judgement, as design rules are not available. The goal of this research is to make a step forward in the design optimization of permeable structures and gain a better understanding of the processes causing the
wave dissipation inside the structure. In this study, scale experiments are conducted in the
wave flume at Delft University of Technology. An array of aluminum cylinders is used as a schematization of the structure, with an element diameter of 4 cm and a minimum spacing of 2 cm. The tested
wave height is 0.13 m,with a water depth of 0.6 m for the first set of experiments. These experiments evaluated
wave transformation through a selected number of configurations. The water depth was 0.55 m for the second set, where the velocities and forces were also measured inside the structure. As the applied
wave periods are short (T = 1 − 2 s), the tested
wave conditions are in the range of small KC-numbers (4 < KC < 13). The first part of this research focuses on effect of different configurations and arrangements on the amount of energy dissipation, by measuring the incoming and reflected
wave heights in front of and behind the structure. For the short waves, the horizontal arrangements dissipate more energy, as energy is dissipated by both the vertical and horizontal
drag forces. However, the effect diminishes with increasing
wave period. Considering the total dissipation and the amount of dissipation per element, the placement of the elements in rows perpendicular to the direction of
wave propagation is found to be the most effective. To study the effect of the element diameter on the dissipation, the results are compared with previous research by Haage (2018) on a model with a diameter and spacing of 2 cm. As with the change in diameter also the structure porosity changed, a direct comparison was not possible and a comparison based on a simplified
drag coefficient is done. No direct effect of the diameter is observed, as the obtained
drag coefficients show the same trend and magnitude when plotted against an adapted Keulegan-Carpenter number (KC∗), which is based on the element spacing instead of diameter. Small KC∗-numbers result in large
drag coefficients,which decrease when KC∗ increases. The second part of this research focuses on the processes inside the structure that cause the energy dissipation. A force and velocity sensor are applied at three locations inside the structure in separate experiments, to determine the relation of the force and velocity inside the structure with the undisturbed values. Two methods are applied for the analysis, based on two different principles. Method 1 is based on the assumption of a constant pair of force coefficients and an increase in velocity inside the structure,…
Advisors/Committee Members: Uijttewaal, Wim (graduation committee), Gijón Mancheño, Alejandra (mentor), Sirks, Emma (mentor), Kuiper, Coen (graduation committee), Lanzafame, Robert (graduation committee), Winterwerp, Han (graduation committee), Delft University of Technology (degree granting institution).
Subjects/Keywords: Building with Nature; BioManCo; Drag coefficients; Wave dissipation; Physical scale model; Dalrymple; Permeable structures; Force measurements; Velocity measurements; Morison's equation; Cylinders; Mangroves
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APA ·
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Export
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Manager
APA (6th Edition):
Jansen, W. (. (2019). Wave dissipation in a permeable structure: Experimental research on the physical processes causing energy dissipation inside an array of cylinders. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:acce330d-968a-46a7-853f-73137b06002a
Chicago Manual of Style (16th Edition):
Jansen, Wiljan (author). “Wave dissipation in a permeable structure: Experimental research on the physical processes causing energy dissipation inside an array of cylinders.” 2019. Masters Thesis, Delft University of Technology. Accessed January 24, 2021.
http://resolver.tudelft.nl/uuid:acce330d-968a-46a7-853f-73137b06002a.
MLA Handbook (7th Edition):
Jansen, Wiljan (author). “Wave dissipation in a permeable structure: Experimental research on the physical processes causing energy dissipation inside an array of cylinders.” 2019. Web. 24 Jan 2021.
Vancouver:
Jansen W(. Wave dissipation in a permeable structure: Experimental research on the physical processes causing energy dissipation inside an array of cylinders. [Internet] [Masters thesis]. Delft University of Technology; 2019. [cited 2021 Jan 24].
Available from: http://resolver.tudelft.nl/uuid:acce330d-968a-46a7-853f-73137b06002a.
Council of Science Editors:
Jansen W(. Wave dissipation in a permeable structure: Experimental research on the physical processes causing energy dissipation inside an array of cylinders. [Masters Thesis]. Delft University of Technology; 2019. Available from: http://resolver.tudelft.nl/uuid:acce330d-968a-46a7-853f-73137b06002a
14.
CHEN HAOLIANG.
Numerical study of solitary wave propagating through vegetation.
Degree: 2010, National University of Singapore
URL: http://scholarbank.nus.edu.sg/handle/10635/19029
Subjects/Keywords: vegetation; solitary wave; runup; numerical modeling; drag force coefficient; inertial force coefficient
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APA (6th Edition):
HAOLIANG, C. (2010). Numerical study of solitary wave propagating through vegetation. (Thesis). National University of Singapore. Retrieved from http://scholarbank.nus.edu.sg/handle/10635/19029
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
HAOLIANG, CHEN. “Numerical study of solitary wave propagating through vegetation.” 2010. Thesis, National University of Singapore. Accessed January 24, 2021.
http://scholarbank.nus.edu.sg/handle/10635/19029.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
HAOLIANG, CHEN. “Numerical study of solitary wave propagating through vegetation.” 2010. Web. 24 Jan 2021.
Vancouver:
HAOLIANG C. Numerical study of solitary wave propagating through vegetation. [Internet] [Thesis]. National University of Singapore; 2010. [cited 2021 Jan 24].
Available from: http://scholarbank.nus.edu.sg/handle/10635/19029.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
HAOLIANG C. Numerical study of solitary wave propagating through vegetation. [Thesis]. National University of Singapore; 2010. Available from: http://scholarbank.nus.edu.sg/handle/10635/19029
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Virginia Tech
15.
Plumley, Ryan W.
Conceptual Assessment of an Oblique Flying Wing Aircraft Including Control and Trim Characteristics.
Degree: MS, Aerospace and Ocean Engineering, 2008, Virginia Tech
URL: http://hdl.handle.net/10919/31417
► A method was developed to assist with the understanding of a unique configuration and investigate some of its stability and control attributes. Oblique wing aircraft…
(more)
▼ A method was developed to assist with the understanding of a unique configuration and investigate some of its stability and control attributes. Oblique wing aircraft concepts are a design option that is well understood, but has yet to be used in a production aircraft. Risk involved in choosing such a design can be averted through additional knowledge early in the concept evaluation phase.
Analysis tools commonly used in early conceptual level analysis were evaluated for applicability to a non-standard aircraft design such as an oblique flying wing. Many tools used in early analyses make assumptions that are incompatible with the slewed wing configuration of the vehicle.
Using a simplified set of tools, an investigation of a unique configuration was done as well as showing that the aircraft could be trimmed at given conditions.
Wave drag was investigated to determine benefits for an oblique flying wing. This form of
drag was reduced by the distribution of volume afforded by the slewing of the aircraftâ s wing. Once a reasonable concept was developed, aerodynamic conditions were investigated for static stability of the aircraft. Longitudinal and lateral trim were established simultaneously due to its asymmetric nature.
Advisors/Committee Members: Mason, William H. (committeechair), Woolsey, Craig A. (committee member), Patil, Mayuresh J. (committee member).
Subjects/Keywords: Stability and Control; Vortex Lattice; OFW; Oblique Flying Wing; Wave Drag
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APA (6th Edition):
Plumley, R. W. (2008). Conceptual Assessment of an Oblique Flying Wing Aircraft Including Control and Trim Characteristics. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/31417
Chicago Manual of Style (16th Edition):
Plumley, Ryan W. “Conceptual Assessment of an Oblique Flying Wing Aircraft Including Control and Trim Characteristics.” 2008. Masters Thesis, Virginia Tech. Accessed January 24, 2021.
http://hdl.handle.net/10919/31417.
MLA Handbook (7th Edition):
Plumley, Ryan W. “Conceptual Assessment of an Oblique Flying Wing Aircraft Including Control and Trim Characteristics.” 2008. Web. 24 Jan 2021.
Vancouver:
Plumley RW. Conceptual Assessment of an Oblique Flying Wing Aircraft Including Control and Trim Characteristics. [Internet] [Masters thesis]. Virginia Tech; 2008. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/10919/31417.
Council of Science Editors:
Plumley RW. Conceptual Assessment of an Oblique Flying Wing Aircraft Including Control and Trim Characteristics. [Masters Thesis]. Virginia Tech; 2008. Available from: http://hdl.handle.net/10919/31417
Delft University of Technology
16.
Hendrix, Emile (author).
Marine Diesel engine response to ventilation loads.
Degree: 2020, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:d3b0eb0f-a2e0-4056-b934-60ae02d4bfec
► Ventilation events are the result of masses of air being transported from the water surface along the hull, through the propeller plane. Previous research in…
(more)
▼ Ventilation events are the result of masses of air being transported from the water surface along the hull, through the propeller plane. Previous research in literature has shown that ventilation induces large and sudden variations of the load on the propeller. The response of the propulsion system had not been documented before. This is a problem with practical and theoretical relevance as both operators and designers of ships and propulsion systems cannot predict the response of these systems to these significant and sudden variations of the propeller-load. The problem can manifest itself in different ways. A first example lies in a possible loss of propulsion and the damages that could incur. A second example lies in the possible installation of too much engine power to respond to unpredictable load-variations such as those incurred by ventilation events. Increased understanding of the relation between
wave properties, -height and -frequency, and the response of a marine Diesel engine, -speed and -torque, subjected to
wave-induced ventilation, is the goal of this thesis and leads to the main research question: How does a marine Diesel engine respond to off-design loads, and in particular to frequently varying loads resulting from propeller ventilation? It focuses on the response of the prime-mover to variations of the propeller-load imposed by ventilation events. The scope of this thesis covers a monohull coaster with a medium-speed marine Diesel engine moving forward in head seas. A model is proposed based on the description of immersion by Journée and Massie (2001) [19]. It consists of three sub-models that describe vessel-motion, the propeller and the prime-mover. The vessel-motion is described with a combination of potential-flow based methods and viscous theory. A quasi-static approach is proposed to describe the influence of ventilation on propeller-functioning. The prime-mover is modelled with a closed-cylinder process and an idealised first-order turbo-charger model that applies the exhaust-flow temperature of the closed-cylinder process to describe the charge-pressure. Three limits to this model lie in the application of vessel-motion data in a limited, positive domain, the application of 1st quadrant propeller data and the propeller envelope. This model uses input consisting of waves and the engine speed setpoint. The output consists of the rotational speed and produced torque of the prime-mover subjected to ventilation. Verification showed responses comparable to, and in the range and time frame of experimental results by Koushan (2007) [21]. Validation efforts lie beyond the scope of this thesis. Experiments by means of simulations have been performed for two engine speed setpoints and different
wave-types describing head seas: Regular waves characterised by low frequencies, -characterised by high frequencies and -characterised by different
wave amplitudes. A final experiment subjected the model to an adverse long-crested
wave-spectrum for ocean waves. The research at hand found that the propeller…
Advisors/Committee Members: Visser, K. (graduation committee), Schreier, S. (graduation committee), Vrijdag, A. (mentor), Delft University of Technology (degree granting institution).
Subjects/Keywords: Marine; propeller; ventilation; Diesel engine; Vessel motions; immersion; Two-phase flow; thrust loss; response; Turbocharger; Quasi Static; simulations; potential flow theory; Froude scaling; Viscous drag; Combustion Simulation; Heat and Mass Transfer; RAO; Wave modeling; Linear wave theory; fourier analysis; EEDI
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APA (6th Edition):
Hendrix, E. (. (2020). Marine Diesel engine response to ventilation loads. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:d3b0eb0f-a2e0-4056-b934-60ae02d4bfec
Chicago Manual of Style (16th Edition):
Hendrix, Emile (author). “Marine Diesel engine response to ventilation loads.” 2020. Masters Thesis, Delft University of Technology. Accessed January 24, 2021.
http://resolver.tudelft.nl/uuid:d3b0eb0f-a2e0-4056-b934-60ae02d4bfec.
MLA Handbook (7th Edition):
Hendrix, Emile (author). “Marine Diesel engine response to ventilation loads.” 2020. Web. 24 Jan 2021.
Vancouver:
Hendrix E(. Marine Diesel engine response to ventilation loads. [Internet] [Masters thesis]. Delft University of Technology; 2020. [cited 2021 Jan 24].
Available from: http://resolver.tudelft.nl/uuid:d3b0eb0f-a2e0-4056-b934-60ae02d4bfec.
Council of Science Editors:
Hendrix E(. Marine Diesel engine response to ventilation loads. [Masters Thesis]. Delft University of Technology; 2020. Available from: http://resolver.tudelft.nl/uuid:d3b0eb0f-a2e0-4056-b934-60ae02d4bfec
17.
Read, Douglas.
A Drag Estimate for Concept-Stage Ship Design Optimization.
Degree: PhD, Interdisciplinary Program, 2009, University of Maine
URL: https://digitalcommons.library.umaine.edu/etd/545
► During the initial phases of ship design, the naval architect would like to have as much information as possible about the design space. This…
(more)
▼ During the initial phases of ship design, the naval architect would like to have as much information as possible about the design space. This information not only helps determine a good set of initial characteristics, it allows for informed design changes when reacting to evolving requirements. One of the most difficult performance measures to evaluate is the ship
wave drag. This estimate is important in an optimization, because wetted surface and
wave drag must be balanced. Multi-parameter optimization algorithms exist, but need a very fast and inexpensive fitness evaluation for them to be effective. Even though linear theory does capture some of the physics of the problem, it has long been out of favor due to its tendency to grossly over-estimate the
wave drag. The other options available are parametric
drag estimates and state-of-the-art boundary element codes. Here we present an intermediate method that makes a parametric correction to the linear theory using an artificial neural network. The method starts with a training set consisting of a large number of panel code evaluations for a systematic hull series, and then uses two approaches to the parametric correction. The first method uses the ratio of linear theory to panel code data as targets for an artificial neural network with parametric inputs. In the second method, we re-derive the linear theory with a new boundary condition, leading to a waterline integral term with unknown coefficients. The linear theory error is then used in a constrained minimization problem to solve for the unknown coefficients, which again provides targets for a neural network. Coupled with a mathematical hull form that can approximate realistic hull shapes, the results show promise for an intermediate
wave drag estimation method that is fast enough to be used as a fitness evaluation for a multi-parameter optimization routine such as a genetic algorithm.
Advisors/Committee Members: Michael Peterson, Donald Grant, Richard Kimball.
Subjects/Keywords: Drag (aerodynamics); Naval architecture; wave mechanics; Aerodynamics and Fluid Mechanics; Engineering; Mechanical Engineering
…described by a centerplane source distribution .
28
Figure 2.3
Steps of the wave drag… …1. Introduction
1.1
Background
Ship wave drag has traditionally been one of the most… …the wave drag have been parametric methods developed from regression analysis of
the… …One of the main goals of understanding the wave drag at the concept design
stage is to… …balance the proportions of wave and frictional components of the total
drag. The relative…
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APA (6th Edition):
Read, D. (2009). A Drag Estimate for Concept-Stage Ship Design Optimization. (Doctoral Dissertation). University of Maine. Retrieved from https://digitalcommons.library.umaine.edu/etd/545
Chicago Manual of Style (16th Edition):
Read, Douglas. “A Drag Estimate for Concept-Stage Ship Design Optimization.” 2009. Doctoral Dissertation, University of Maine. Accessed January 24, 2021.
https://digitalcommons.library.umaine.edu/etd/545.
MLA Handbook (7th Edition):
Read, Douglas. “A Drag Estimate for Concept-Stage Ship Design Optimization.” 2009. Web. 24 Jan 2021.
Vancouver:
Read D. A Drag Estimate for Concept-Stage Ship Design Optimization. [Internet] [Doctoral dissertation]. University of Maine; 2009. [cited 2021 Jan 24].
Available from: https://digitalcommons.library.umaine.edu/etd/545.
Council of Science Editors:
Read D. A Drag Estimate for Concept-Stage Ship Design Optimization. [Doctoral Dissertation]. University of Maine; 2009. Available from: https://digitalcommons.library.umaine.edu/etd/545
University of Florida
18.
Marin, Justin.
Wave Loading on a Horizontal Plate.
Degree: MS, Coastal and Oceanographic Engineering - Civil and Coastal Engineering, 2009, University of Florida
URL: https://ufdc.ufl.edu/UFE0024473
► A theoretical, numerical, and experimental study of vertical forces due to non-breaking, monochromatic water waves propagating past a thin, horizontal rectangular plate structure is presented.…
(more)
▼ A theoretical, numerical, and experimental study of vertical forces due to non-breaking, monochromatic water waves propagating past a thin, horizontal rectangular plate structure is presented. A theoretical model is developed as the sum of the individual forcing components,
drag, inertia, buoyancy, and slamming. A numerical model for evaluating the mathematical model is also developed that includes a stream function theory algorithm for computing the
wave kinematics. Experimental tests were conducted for a range of water depths,
wave conditions and structure locations relative to the still water level.
Drag and inertia coefficients for the theoretical model were determined from the physical model test results. An empirical relationship for slamming was developed. There is good agreement between the numerical and experimental results. Also presented are recommendations for future work. ( en )
Advisors/Committee Members: Sheppard, Donald M. (committee chair), Valle-Levinson, Arnoldo (committee member).
Subjects/Keywords: Drag coefficient; Flat plates; Inertia; Kinematics; Mass; Modeling; Predictive modeling; Time series; Water depth; Waves; forces, impact, loading, slamming, wave
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APA (6th Edition):
Marin, J. (2009). Wave Loading on a Horizontal Plate. (Masters Thesis). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0024473
Chicago Manual of Style (16th Edition):
Marin, Justin. “Wave Loading on a Horizontal Plate.” 2009. Masters Thesis, University of Florida. Accessed January 24, 2021.
https://ufdc.ufl.edu/UFE0024473.
MLA Handbook (7th Edition):
Marin, Justin. “Wave Loading on a Horizontal Plate.” 2009. Web. 24 Jan 2021.
Vancouver:
Marin J. Wave Loading on a Horizontal Plate. [Internet] [Masters thesis]. University of Florida; 2009. [cited 2021 Jan 24].
Available from: https://ufdc.ufl.edu/UFE0024473.
Council of Science Editors:
Marin J. Wave Loading on a Horizontal Plate. [Masters Thesis]. University of Florida; 2009. Available from: https://ufdc.ufl.edu/UFE0024473
19.
Waddington, Michael Jon.
Development of an Interactive Wave Drag Capability for the OpenVSP Parametric Geometry Tool.
Degree: MS, Aerospace Engineering, 2015, Cal Poly
URL: https://digitalcommons.calpoly.edu/theses/1435
;
10.15368/theses.2015.126
► Minimizing wave drag is critical to successful and efficient transonic and supersonic flight. Area-ruling is the process of managing the cross-sectional area of an…
(more)
▼ Minimizing
wave drag is critical to successful and efficient transonic and supersonic flight. Area-ruling is the process of managing the cross-sectional area of an aircraft to lessen the
wave drag experienced in flight. Effectively calculating the necessary areas for a given aircraft can be difficult, and existing tools for conducting a
wave drag analysis often carry limitations in both functionality and availability.
In this work, the author utilized an existing parametric geometry tool named OpenVSP to create an interactive design tool for approximating zero-lift
wave drag. Here, the
wave drag calculation methodology used in industry for decades is combined with the powerful geometry engine of OpenVSP, which was recently heavily upgraded at the start of 2015. Various visual aids allow users of this OpenVSP
wave drag tool to interact with area and
wave drag results and develop intuition for supersonic aircraft design using the area rule approach. OpenVSP allows geometry changes to be made quickly, enabling rapid reanalysis by the
wave drag tool for expeditious comparison of results across the design space.
Advisors/Committee Members: Robert A. McDonald.
Subjects/Keywords: Geometry tool; wave drag; OpenVSP; aircraft design; supersonic; Other Aerospace Engineering
…wave drag tool information between OpenVSP classes. . . . . . . . . . 28
5.2
Aircraft model… …43
7.1
Highlighting the Wave Drag option from the OpenVSP Analysis pull-down
menu… …46
7.2
Default wave drag tool GUI… …47
7.3
“Run” tab of the wave drag tool GUI… …48
7.4
“Flow Faces” tab of the wave drag tool GUI, with example subsurfaces shown
as a…
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APA (6th Edition):
Waddington, M. J. (2015). Development of an Interactive Wave Drag Capability for the OpenVSP Parametric Geometry Tool. (Masters Thesis). Cal Poly. Retrieved from https://digitalcommons.calpoly.edu/theses/1435 ; 10.15368/theses.2015.126
Chicago Manual of Style (16th Edition):
Waddington, Michael Jon. “Development of an Interactive Wave Drag Capability for the OpenVSP Parametric Geometry Tool.” 2015. Masters Thesis, Cal Poly. Accessed January 24, 2021.
https://digitalcommons.calpoly.edu/theses/1435 ; 10.15368/theses.2015.126.
MLA Handbook (7th Edition):
Waddington, Michael Jon. “Development of an Interactive Wave Drag Capability for the OpenVSP Parametric Geometry Tool.” 2015. Web. 24 Jan 2021.
Vancouver:
Waddington MJ. Development of an Interactive Wave Drag Capability for the OpenVSP Parametric Geometry Tool. [Internet] [Masters thesis]. Cal Poly; 2015. [cited 2021 Jan 24].
Available from: https://digitalcommons.calpoly.edu/theses/1435 ; 10.15368/theses.2015.126.
Council of Science Editors:
Waddington MJ. Development of an Interactive Wave Drag Capability for the OpenVSP Parametric Geometry Tool. [Masters Thesis]. Cal Poly; 2015. Available from: https://digitalcommons.calpoly.edu/theses/1435 ; 10.15368/theses.2015.126
Delft University of Technology
20.
Suzuki, T.
Wave dissipation over vegetation fields.
Degree: 2011, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:ff8147df-4389-4394-bf0c-3fe50076e557
;
urn:NBN:nl:ui:24-uuid:ff8147df-4389-4394-bf0c-3fe50076e557
;
urn:NBN:nl:ui:24-uuid:ff8147df-4389-4394-bf0c-3fe50076e557
;
http://resolver.tudelft.nl/uuid:ff8147df-4389-4394-bf0c-3fe50076e557
► It has been widely recognized that ongoing climate change, most likely due to human interference with nature, may accelerate sea level rise and increase storm…
(more)
▼ It has been widely recognized that ongoing climate change, most likely due to human interference with nature, may accelerate sea level rise and increase storm intensity. It is therefore urgent to design countermeasures to alleviate the impact of climate change on coastal regions. Apart from the view point of coastal protection, it is also very important for coastal engineers to keep an eye on environmental issues in the coastal region. In this context, vegetation fields such as salt marshes, sea grasses and mangrove forests in coastal regions have started to attract the attention of coastal engineers due to their function as
wave attenuator. However, the
wave attenuation function of a vegetated field is not well understood yet. To utilize coastal vegetation fields as a part of coastal management in practice, it is crucial to accumulate more knowledge about the physical processes, especially the hydraulic processes, and these need to be modeled in a practical sense. Hence, this thesis is intended as an investigation of the process of
wave dissipation over vegetation fields through various approaches, specifically theoretical, physical and numerical studies.
Advisors/Committee Members: Stive, M.J.F., Uijttewaal, W.S.J..
Subjects/Keywords: wave dissipation; bulk drag coefficient; vegetation; CADMAS-SURF/3D; Large-Eddy Simulation; Immersed Boundary Method; SWAN-VEG
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APA (6th Edition):
Suzuki, T. (2011). Wave dissipation over vegetation fields. (Doctoral Dissertation). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:ff8147df-4389-4394-bf0c-3fe50076e557 ; urn:NBN:nl:ui:24-uuid:ff8147df-4389-4394-bf0c-3fe50076e557 ; urn:NBN:nl:ui:24-uuid:ff8147df-4389-4394-bf0c-3fe50076e557 ; http://resolver.tudelft.nl/uuid:ff8147df-4389-4394-bf0c-3fe50076e557
Chicago Manual of Style (16th Edition):
Suzuki, T. “Wave dissipation over vegetation fields.” 2011. Doctoral Dissertation, Delft University of Technology. Accessed January 24, 2021.
http://resolver.tudelft.nl/uuid:ff8147df-4389-4394-bf0c-3fe50076e557 ; urn:NBN:nl:ui:24-uuid:ff8147df-4389-4394-bf0c-3fe50076e557 ; urn:NBN:nl:ui:24-uuid:ff8147df-4389-4394-bf0c-3fe50076e557 ; http://resolver.tudelft.nl/uuid:ff8147df-4389-4394-bf0c-3fe50076e557.
MLA Handbook (7th Edition):
Suzuki, T. “Wave dissipation over vegetation fields.” 2011. Web. 24 Jan 2021.
Vancouver:
Suzuki T. Wave dissipation over vegetation fields. [Internet] [Doctoral dissertation]. Delft University of Technology; 2011. [cited 2021 Jan 24].
Available from: http://resolver.tudelft.nl/uuid:ff8147df-4389-4394-bf0c-3fe50076e557 ; urn:NBN:nl:ui:24-uuid:ff8147df-4389-4394-bf0c-3fe50076e557 ; urn:NBN:nl:ui:24-uuid:ff8147df-4389-4394-bf0c-3fe50076e557 ; http://resolver.tudelft.nl/uuid:ff8147df-4389-4394-bf0c-3fe50076e557.
Council of Science Editors:
Suzuki T. Wave dissipation over vegetation fields. [Doctoral Dissertation]. Delft University of Technology; 2011. Available from: http://resolver.tudelft.nl/uuid:ff8147df-4389-4394-bf0c-3fe50076e557 ; urn:NBN:nl:ui:24-uuid:ff8147df-4389-4394-bf0c-3fe50076e557 ; urn:NBN:nl:ui:24-uuid:ff8147df-4389-4394-bf0c-3fe50076e557 ; http://resolver.tudelft.nl/uuid:ff8147df-4389-4394-bf0c-3fe50076e557
University of Canterbury
21.
Plew, David Russell.
The Hydrodynamic Effects of Long-line Mussel Farms.
Degree: PhD, Civil Engineering, 2005, University of Canterbury
URL: http://dx.doi.org/10.26021/3238
► The hydrodynamic effects of long-line mussel farms are studied through a two-pronged approach. Large-scale hydrodynamic effects are investigated through the use of field measurements, primarily…
(more)
▼ The hydrodynamic effects of long-line mussel farms are studied through a two-pronged approach. Large-scale hydrodynamic effects are investigated through the use of field measurements, primarily at a large mussel farm in Golden Bay, New Zealand (230 long-lines, covering an area of 2.45 km by 0.65 km). The research focuses on three areas: the effect of the farm on currents, mixing and stratification, and the dissipation of wave energy. Measurements are also made of the forces on long-line anchor ropes, and a limited investigation is made of phytoplankton depletion. The second approach is the use of laboratory drag measurements and Particle Tracking Velocimetry (PTV) to study the effect of mussel dropper (vertical lengths of mussel-encrusted crop rope) roughness and spacing on flow at small scales. These experiments provide data on very rough cylinders, and on cylinder arrays. The field measurements show that the local effects of mussel farms on currents are significant, but that magnitudes of the effects depend on dropper density, mussel sizes, orientation of the long-lines to the flow, and other parameters that are necessary to characterise the complex interactions between a farm and the flow. The drag on the submerged structures reduces water velocities within the Golden Bay farm by between 47% and 67%. Mussel farms present a porous obstacle to the flow, and flow that does not pass through the farm must be directed around or beneath it. The field measurements indicate that at the study site, most of the flow is diverted around the farm despite its large horizontal dimensions. The droppers at the study site extend over most of the water column (average dropper length ~ 8 m, average water depth ~ 11 m), providing a restriction to the flow beneath the farm. The strength of the density stratification may also favour a horizontal diversion. The flow around the farm is essentially two-dimensional. This suggests that two-dimensional numerical models should be sufficient to obtain reasonable predictions of the velocity drop within, and the diversion around, mussel farms. A simple two-dimensional pipe-network model gives reasonable estimates of the velocity within the farm, demonstrating that the drag of the farm may be adequately parameterised through local increases of bed friction. A wake in the form of reduced velocities extends downstream of the farm, and a mixing layer analogy suggests that this wake spreads slowly. The downstream extent of the wake cannot be determined, although it is likely to be limited by the tidal excursion. The degree of vertical mixing caused by the flow through a mussel farm cannot be quantified, although there are clear interactions between the stratification and the farm. Two mixing mechanisms are considered. A shear layer is generated beneath the farm due to the difference in velocities between the retarded flow within the farm and the flow beneath. Shear layers beneath mussel farms are likely to be weak unless the ambient currents are strong. It will be necessary for stratification to be…
Subjects/Keywords: aquaculture; mariculture; mussel farming; long-lines; currents; mixing; drag; stratification; wave dissipation; circular cylinders; rough cylinders; surface roughness; cylinder arrays
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APA ·
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MLA ·
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Export
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APA (6th Edition):
Plew, D. R. (2005). The Hydrodynamic Effects of Long-line Mussel Farms. (Doctoral Dissertation). University of Canterbury. Retrieved from http://dx.doi.org/10.26021/3238
Chicago Manual of Style (16th Edition):
Plew, David Russell. “The Hydrodynamic Effects of Long-line Mussel Farms.” 2005. Doctoral Dissertation, University of Canterbury. Accessed January 24, 2021.
http://dx.doi.org/10.26021/3238.
MLA Handbook (7th Edition):
Plew, David Russell. “The Hydrodynamic Effects of Long-line Mussel Farms.” 2005. Web. 24 Jan 2021.
Vancouver:
Plew DR. The Hydrodynamic Effects of Long-line Mussel Farms. [Internet] [Doctoral dissertation]. University of Canterbury; 2005. [cited 2021 Jan 24].
Available from: http://dx.doi.org/10.26021/3238.
Council of Science Editors:
Plew DR. The Hydrodynamic Effects of Long-line Mussel Farms. [Doctoral Dissertation]. University of Canterbury; 2005. Available from: http://dx.doi.org/10.26021/3238
University of New South Wales
22.
Couldrick, Jonathan Stuart.
A study of swept and unswept normal shock wave/turbulent boundary layer interaction and control by piezoelectric flap actuation.
Degree: Aerospace, 2006, University of New South Wales
URL: http://handle.unsw.edu.au/1959.4/38672
;
https://unsworks.unsw.edu.au/fapi/datastream/unsworks:3202/SOURCE01?view=true
► The interaction of a shock wave with a boundary layer is a classic viscous/inviscid interaction problem that occurs over a wide range of high speed…
(more)
▼ The interaction of a shock wave with a boundary layer is a classic viscous/inviscid interaction problem that occurs over a wide range of high speed aerodynamic flows.For example, on transonic wings, in supersonic air intakes, in propelling nozzles at offdesign conditions and on deflected controls at supersonic/transonic speeds, to name a few. The transonic interaction takes place at Mach numbers typically between 1.1 and 1.5. On an aerofoil, its existence can cause problems that range from a mild increase in section drag to flow separation and buffeting. In the absence of separation the drag increase is predominantly due to wave drag, caused by a rise in entropy through the interaction.The control of the turbulent interaction as applied to a transonic aerofoil is addressed in this thesis. However, the work can equally be applied to the control of interaction for numerous other occurrences where a shock meets a turbulent boundary layer. It is assumed that, for both swept normal shock and unswept normal shock interactions, as long as the Mach number normal to the shock is the same, then the interaction, and therefore its control, should be the same.Numerous schemes have been suggested to control such interaction. However, they have generally been marred by the drag reduction obtained being negated by the additional drag due to the power requirements, for example the pumping power in the case of mass transfer and the drag of the devices in the case of vortex generators. A system of piezoelectrically controlled flaps is presented for the control of theinteraction. The flaps would aeroelastically deflect due to the pressure differencecreated by the pressure rise across the shock and by piezoelectrically induced strains.The amount of deflection, and hence the mass flow through the plenum chamber, wouldcontrol the interaction. It is proposed that the flaps will delay separation of theboundary layer whilst reducing wave drag and overcome the disadvantages of previouscontrol methods. Active control can be utilised to optimise the effects of the boundarylayer shock wave interaction as it would allow the ability to control the position of thecontrol region around the original shock position, mass transfer rate and distribution.A number of design options were considered for the integration of the piezoelectricceramic into the flap structure. These included the use of unimorphs, bimorphs andpolymorphs, with the latter capable of being directly employed as the flap. Unimorphs,with an aluminium substrate, produce less deflection than bimorphs and multimorphs.However, they can withstand and overcome the pressure loads associated with SBLIcontrol.For the current experiments, it was found that near optimal control of the swept andunswept shock wave boundary layer interactions was attained with flap deflectionsbetween 1mm and 3mm. However, to obtain the deflection required for optimalperformance in a full scale situation, a more powerful piezoelectric actuator material isrequired than currently available.A theoretical model is…
Subjects/Keywords: Shock wave; boundary layer; viscous/inviscid interaction; transonic aerofoil; swept shock wave; turbulence; pressure sensitive paints; shock waves; piezoelectricity; drag (aerodynamics); flaps; piezoelectric; flap actuators; unimorphs; bimorphs; polymorphs; deflection
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APA (6th Edition):
Couldrick, J. S. (2006). A study of swept and unswept normal shock wave/turbulent boundary layer interaction and control by piezoelectric flap actuation. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/38672 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:3202/SOURCE01?view=true
Chicago Manual of Style (16th Edition):
Couldrick, Jonathan Stuart. “A study of swept and unswept normal shock wave/turbulent boundary layer interaction and control by piezoelectric flap actuation.” 2006. Doctoral Dissertation, University of New South Wales. Accessed January 24, 2021.
http://handle.unsw.edu.au/1959.4/38672 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:3202/SOURCE01?view=true.
MLA Handbook (7th Edition):
Couldrick, Jonathan Stuart. “A study of swept and unswept normal shock wave/turbulent boundary layer interaction and control by piezoelectric flap actuation.” 2006. Web. 24 Jan 2021.
Vancouver:
Couldrick JS. A study of swept and unswept normal shock wave/turbulent boundary layer interaction and control by piezoelectric flap actuation. [Internet] [Doctoral dissertation]. University of New South Wales; 2006. [cited 2021 Jan 24].
Available from: http://handle.unsw.edu.au/1959.4/38672 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:3202/SOURCE01?view=true.
Council of Science Editors:
Couldrick JS. A study of swept and unswept normal shock wave/turbulent boundary layer interaction and control by piezoelectric flap actuation. [Doctoral Dissertation]. University of New South Wales; 2006. Available from: http://handle.unsw.edu.au/1959.4/38672 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:3202/SOURCE01?view=true
Missouri University of Science and Technology
23.
Alhaj, Abdullah Hadi Zaid.
Bridge deck assessment using visual inspection, ground penetrating radar, portable seismic property analyzer-ultrasonic surface wave, hammer sounding and chain drag.
Degree: M.S. in Geological Engineering, Geological Engineering, Missouri University of Science and Technology
URL: https://scholarsmine.mst.edu/masters_theses/7817
► "Integrated non-destructive techniques were utilized to assess the condition of a reinforced concrete bridge deck. There were two main objectives accomplished. The first objective…
(more)
▼ "Integrated non-destructive techniques were utilized to assess the condition of a reinforced concrete bridge deck. There were two main objectives accomplished. The first objective was to assess the integrity of the reinforced concrete bridge deck using four non-destructive techniques, namely visual inspection, ground penetrating radar, portable seismic property analyzer-ultrasonic surface wave, and hammer sounding and chain drag. Visual inspection data were used to identify signs of deterioration on surface of the bridge deck such as cracking, concrete leaching, and reinforcement corrosion. Ground penetrating radar data were used to determine the relative condition of the bridge deck. However, due to the significant differences in depth of the embedded reinforcements, ground penetrating radar data were not useful in terms of assessing the overall condition of the bridge deck. Portable seismic property analyzer-ultrasonic surface wave data were used to determine the concrete quality of the bridge deck by estimating averag Young's modulus (elastic modulus). Hammer sounding and chain drag data were used to identify non-delaminated and severe delaminated areas in the bridge deck. The second objective was to demonstrate the effect of temperature and moisture content changes on ground penetrating radar signal amplitude. Ground penetrating radar signal amplitude variations associated with different weather condition of temperature and moisture changes were evaluated. Ground penetrating radar signal amplitude was increasingly attenuated during low temperature and high moisture content. In contrast, ground penetrating radar signal amplitude was decreasingly attenuated during high temperature low moisture content" – Abstract, page iii.
Subjects/Keywords: Bridge deck assessment; Ground penetrating radar (GPR); Hammer sounding and chain drag; Portable seismic property analyzer (PSPA); Ultrasonic surface wave (USW); Using non-destructive techniques for bridge deck assessment; Geological Engineering; Geophysics and Seismology
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MLA ·
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APA (6th Edition):
Alhaj, A. H. Z. (n.d.). Bridge deck assessment using visual inspection, ground penetrating radar, portable seismic property analyzer-ultrasonic surface wave, hammer sounding and chain drag. (Masters Thesis). Missouri University of Science and Technology. Retrieved from https://scholarsmine.mst.edu/masters_theses/7817
Note: this citation may be lacking information needed for this citation format:
No year of publication.
Chicago Manual of Style (16th Edition):
Alhaj, Abdullah Hadi Zaid. “Bridge deck assessment using visual inspection, ground penetrating radar, portable seismic property analyzer-ultrasonic surface wave, hammer sounding and chain drag.” Masters Thesis, Missouri University of Science and Technology. Accessed January 24, 2021.
https://scholarsmine.mst.edu/masters_theses/7817.
Note: this citation may be lacking information needed for this citation format:
No year of publication.
MLA Handbook (7th Edition):
Alhaj, Abdullah Hadi Zaid. “Bridge deck assessment using visual inspection, ground penetrating radar, portable seismic property analyzer-ultrasonic surface wave, hammer sounding and chain drag.” Web. 24 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
No year of publication.
Vancouver:
Alhaj AHZ. Bridge deck assessment using visual inspection, ground penetrating radar, portable seismic property analyzer-ultrasonic surface wave, hammer sounding and chain drag. [Internet] [Masters thesis]. Missouri University of Science and Technology; [cited 2021 Jan 24].
Available from: https://scholarsmine.mst.edu/masters_theses/7817.
Note: this citation may be lacking information needed for this citation format:
No year of publication.
Council of Science Editors:
Alhaj AHZ. Bridge deck assessment using visual inspection, ground penetrating radar, portable seismic property analyzer-ultrasonic surface wave, hammer sounding and chain drag. [Masters Thesis]. Missouri University of Science and Technology; Available from: https://scholarsmine.mst.edu/masters_theses/7817
Note: this citation may be lacking information needed for this citation format:
No year of publication.
University of New Orleans
24.
Zhou, Zhengquan.
A Theory and Analysis of Planing Catamarans in Calm and Rough Water.
Degree: PhD, Naval Architecture and Marine Engineering, 2003, University of New Orleans
URL: https://scholarworks.uno.edu/td/28
► A planing catamaran is a high-powered, twin-hull water craft that develops the lift which supports its weight, primarily through hydrodynamic water pressure. Presently, there is…
(more)
▼ A planing catamaran is a high-powered, twin-hull water craft that develops the lift which supports its weight, primarily through hydrodynamic water pressure. Presently, there is increasing demand to further develop the catamaran's planing and seakeeping characteristics so that it is more effectively applied in today's modern military and pleasure craft, and offshore industry supply vessels. Over the course of the past ten years, Vorus (1994,1996,1998,2000) has systematically conducted a series of research works on planing craft hydrodynamics. Based on Vorus' planing monohull theory, he has developed and implemented a first order nonlinear model for planing catamarans, embodied in the computer code CatSea. This model is currently applied in planing catamaran design. However, due to the greater complexity of the catamaran flow physics relative to the monohull, Vorus's (first order) catamaran model implemented some important approximations and simplifications which were not considered necessary in the monohull work. The research of this thesis is for relieving the initially implemented approximations in Vorus's first order planing catamaran theory, and further developing and extending the theory and application beyond that currently in use in CatSea. This has been achieved through a detailed theoretical analysis, algorithm development, and careful coding. The research result is a new, complete second order nonlinear hydrodynamic theory for planing catamarans. A detailed numerical comparison of the Vorus's first order nonlinear theory and the second order nonlinear theory developed here is carried out. The second order nonlinear theory and algorithms have been incorporated into a new catamaran design code (NewCat). A detailed mathematical formulation of the base first order CatSea theory, followed by the extended second order theory, is completely documented in this thesis.
Advisors/Committee Members: Vorus, William, Wei, Dongming, Falzarano, Jeffrey.
Subjects/Keywords: vortex strength distribution; random wave; nonlinear wave; high speed jet flow; water jet; fast ship; vessel design; drag and resistance dynamic lift; high speed craft; Planing craft; planing boat; impact hydrodynamics; steady planing; seakeeping; slender body theory; time marching; singular integral; special function; ship motion
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Zhou, Z. (2003). A Theory and Analysis of Planing Catamarans in Calm and Rough Water. (Doctoral Dissertation). University of New Orleans. Retrieved from https://scholarworks.uno.edu/td/28
Chicago Manual of Style (16th Edition):
Zhou, Zhengquan. “A Theory and Analysis of Planing Catamarans in Calm and Rough Water.” 2003. Doctoral Dissertation, University of New Orleans. Accessed January 24, 2021.
https://scholarworks.uno.edu/td/28.
MLA Handbook (7th Edition):
Zhou, Zhengquan. “A Theory and Analysis of Planing Catamarans in Calm and Rough Water.” 2003. Web. 24 Jan 2021.
Vancouver:
Zhou Z. A Theory and Analysis of Planing Catamarans in Calm and Rough Water. [Internet] [Doctoral dissertation]. University of New Orleans; 2003. [cited 2021 Jan 24].
Available from: https://scholarworks.uno.edu/td/28.
Council of Science Editors:
Zhou Z. A Theory and Analysis of Planing Catamarans in Calm and Rough Water. [Doctoral Dissertation]. University of New Orleans; 2003. Available from: https://scholarworks.uno.edu/td/28
. 
Open Access Theses and Dissertations
