subject:(High order method)

Colorado School of Mines

1. Morgenstern, Charles O. High-order high-performance computing algorithms for wave propagation in heterogeneous media.

Degree: PhD, Applied Mathematics and Statistics, 2016, Colorado School of Mines

URL: http://hdl.handle.net/11124/170316

► Understanding the propagation of waves using computer models is important for several applications. Major challenges for developing efficient wave propagation computer models include incorporating heterogeneous… (more)

Subjects/Keywords: boundary element method; finite element method; high-order; indefinite systems; iterative methods; wave propagation

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APA (6^th Edition):

Morgenstern, C. O. (2016). High-order high-performance computing algorithms for wave propagation in heterogeneous media. (Doctoral Dissertation). Colorado School of Mines. Retrieved from http://hdl.handle.net/11124/170316

Chicago Manual of Style (16^th Edition):

Morgenstern, Charles O. “High-order high-performance computing algorithms for wave propagation in heterogeneous media.” 2016. Doctoral Dissertation, Colorado School of Mines. Accessed January 17, 2021. http://hdl.handle.net/11124/170316.

MLA Handbook (7^th Edition):

Morgenstern, Charles O. “High-order high-performance computing algorithms for wave propagation in heterogeneous media.” 2016. Web. 17 Jan 2021.

Vancouver:

Morgenstern CO. High-order high-performance computing algorithms for wave propagation in heterogeneous media. [Internet] [Doctoral dissertation]. Colorado School of Mines; 2016. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/11124/170316.

Council of Science Editors:

Morgenstern CO. High-order high-performance computing algorithms for wave propagation in heterogeneous media. [Doctoral Dissertation]. Colorado School of Mines; 2016. Available from: http://hdl.handle.net/11124/170316

2. Gao, Kai. A Study in the Frequency Warping of Time-Domain Methods .

Degree: 2015, University of Ottawa

URL: http://hdl.handle.net/10393/32331

► This thesis develops a study for the frequency warping introduced by time-domain methods. The work in this study focuses first on the time-domain methods used… (more)

Subjects/Keywords: Shooting method; Warping error; High-order method

…viii 68 List of Algorithms 1 Shooting method based on Obreshkov-based high-order methods… …αi , βi Coefficients in Obreshkov-based high-order method G̃, C̃, f˜, b̃, ξ Augmented… …high-order integration method can reduce the warping error compared with the classical low… …the high order method and compare it with those of classical low-order methods. Theoretical… …As a result, adopting the high-order integration method can not only achieve better…

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APA (6^th Edition):

Gao, K. (2015). A Study in the Frequency Warping of Time-Domain Methods . (Thesis). University of Ottawa. Retrieved from http://hdl.handle.net/10393/32331

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

Chicago Manual of Style (16^th Edition):

Gao, Kai. “A Study in the Frequency Warping of Time-Domain Methods .” 2015. Thesis, University of Ottawa. Accessed January 17, 2021. http://hdl.handle.net/10393/32331.

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

MLA Handbook (7^th Edition):

Gao, Kai. “A Study in the Frequency Warping of Time-Domain Methods .” 2015. Web. 17 Jan 2021.

Vancouver:

Gao K. A Study in the Frequency Warping of Time-Domain Methods . [Internet] [Thesis]. University of Ottawa; 2015. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/10393/32331.

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

Council of Science Editors:

Gao K. A Study in the Frequency Warping of Time-Domain Methods . [Thesis]. University of Ottawa; 2015. Available from: http://hdl.handle.net/10393/32331

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

Brunel University

3. Mukhamedov, Farukh. High performance computing for the discontinuous Galerkin methods.

Degree: PhD, 2018, Brunel University

URL: http://bura.brunel.ac.uk/handle/2438/16769 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.765015

► Discontinuous Galerkin methods form a class of numerical methods to find a solution of partial differential equations by combining features of finite element and finite… (more)

▼ Discontinuous Galerkin methods form a class of numerical methods to find a solution of partial differential equations by combining features of finite element and finite volume methods. Methods are defined using a weak form of a particular model problem, allowing for discontinuities in the discrete trial and test spaces. Using a discontinuous discrete space mesh provides proper flexibility and a compact discretisation pattern, allowing a multidomain and multiphysics simulation. Discontinuous Galerkin methods with a higher approximation polynomial order, the socalled p-version, performs better in terms of convergence rate, compared with the low order h-version with smaller element sizes and bigger mesh. However, the condition number of the Galerkin system grows subsequently. This causes surge in the amount of required storage, computational complexity and in the time required for computation. We use the following three approaches to keep the advantages and eliminate the disadvantages. The first approach will be a specific choice of basis functions which we call C1 polynomials. These ensure that the majority of integrals over the edge of the mesh elements disappears. This reduces the total number of non-zero elements in the resulting system. This decreases the computational complexity without loss in precision. This approach does not affect the number of iterations required by chosen Conjugate Gradients method when compared to the other choice of basis functions. It actually decreases the total number of algebraic operations performed. The second approach is the introduction of suitable preconditioners. In our case, the Additive two-layer Schwarz method, developed in [4], for the iterative Conjugate Gradients method is considered. This directly affects the spectral condition number of the system matrix and decreases the number of iterations required for the computation. This approach, however, increases the total number of algebraic operations and might require more operational time. To tackle the rise in the number of algebraic operations, we introduced a modified Additive two-layer non-overlapping Schwarz method with a Multigrid process. This using a fixed low-order approximation polynomial degree on a coarse grid. We show that this approach is spectrally equivalent to the first preconditioner, and requires less time for computation. The third approach is a development of an efficient mathematical framework for distributed data structure. This allows a high performance, massively parallel, implementation of the discontinuous Galerkin method. We demonstrate that it is possible to exploit properties of the system matrix and C1 polynomials as basis functions to optimize the parallel structures. The previously mentioned parallel data structure allows us to parallelize at the same time both the matrix-vector multiplication routines for the Conjugate Gradients method, as well as the preconditioner routines on the solver level. This minimizes the transfer ratio amongst the distributed system. Finally, we combined all three…

Subjects/Keywords: High order polynomial approximation FEM; C1 basis functions; Schwarz method; Multigrid method; Parallel computing with OpenMP and MPI

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APA (6^th Edition):

Mukhamedov, F. (2018). High performance computing for the discontinuous Galerkin methods. (Doctoral Dissertation). Brunel University. Retrieved from http://bura.brunel.ac.uk/handle/2438/16769 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.765015

Chicago Manual of Style (16^th Edition):

Mukhamedov, Farukh. “High performance computing for the discontinuous Galerkin methods.” 2018. Doctoral Dissertation, Brunel University. Accessed January 17, 2021. http://bura.brunel.ac.uk/handle/2438/16769 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.765015.

MLA Handbook (7^th Edition):

Mukhamedov, Farukh. “High performance computing for the discontinuous Galerkin methods.” 2018. Web. 17 Jan 2021.

Vancouver:

Mukhamedov F. High performance computing for the discontinuous Galerkin methods. [Internet] [Doctoral dissertation]. Brunel University; 2018. [cited 2021 Jan 17]. Available from: http://bura.brunel.ac.uk/handle/2438/16769 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.765015.

Council of Science Editors:

Mukhamedov F. High performance computing for the discontinuous Galerkin methods. [Doctoral Dissertation]. Brunel University; 2018. Available from: http://bura.brunel.ac.uk/handle/2438/16769 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.765015

University of Kansas

4. Shi, Lei. Adaptive High-Order Differential Formulation for the Compressible Navier-Stokes Equations.

Degree: PhD, Aerospace Engineering, 2014, University of Kansas

URL: http://hdl.handle.net/1808/27533

► High-order methods have the potential to achieve higher accuracy at lower cost than lower order methods. This potential has been demonstrated conclusively for smooth problems… (more)

Subjects/Keywords: Aerospace engineering; Adaptive Method; Adjoint-based Adaptation; Computational Fluid Dynamics; High-order Method; Navier-Stokes Equations

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APA (6^th Edition):

Shi, L. (2014). Adaptive High-Order Differential Formulation for the Compressible Navier-Stokes Equations. (Doctoral Dissertation). University of Kansas. Retrieved from http://hdl.handle.net/1808/27533

Chicago Manual of Style (16^th Edition):

Shi, Lei. “Adaptive High-Order Differential Formulation for the Compressible Navier-Stokes Equations.” 2014. Doctoral Dissertation, University of Kansas. Accessed January 17, 2021. http://hdl.handle.net/1808/27533.

MLA Handbook (7^th Edition):

Shi, Lei. “Adaptive High-Order Differential Formulation for the Compressible Navier-Stokes Equations.” 2014. Web. 17 Jan 2021.

Vancouver:

Shi L. Adaptive High-Order Differential Formulation for the Compressible Navier-Stokes Equations. [Internet] [Doctoral dissertation]. University of Kansas; 2014. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1808/27533.

Council of Science Editors:

Shi L. Adaptive High-Order Differential Formulation for the Compressible Navier-Stokes Equations. [Doctoral Dissertation]. University of Kansas; 2014. Available from: http://hdl.handle.net/1808/27533

Iowa State University

5. Gurrala, Praveen. Full-wave modeling of ultrasonic scattering for non-destructive evaluation.

Degree: 2020, Iowa State University

URL: https://lib.dr.iastate.edu/etd/18133

► The physical modeling and simulation of nondestructive evaluation (NDE) measurements has a major role in the advancement of NDE and structural health monitoring (SHM). In… (more)

▼ The physical modeling and simulation of nondestructive evaluation (NDE) measurements has a major role in the advancement of NDE and structural health monitoring (SHM). In ultrasonic NDE (UNDE) simulations, evaluating the scattering of ultrasound by defects is a computationally-intensive process. Many UNDE system models treat the scattering process using exact analytical methods or high-frequency approximations such as the Kirchhoff approximation (KA) to make the simulation effort tractable. These methods naturally have a limited scope. This thesis aims to supplement the existing scattering models with fast and memory-efficient full-wave models that are based on the boundary element method (BEM). For computational efficiency, such full-wave models should be applied only to those problems wherein the existing approximation methods are not suitable. Therefore, the adequacy of different scattering models for representing various test scenarios has to be studied. Although analyzing scattering models by themselves is helpful, their true adequacy is revealed only when they are combined with models of other elements of the NDE system, and the resulting predictions are evaluated against measurements. Very few comprehensive studies of this nature exist, particularly for full-wave scattering models. To fill this gap, two different scattering models – the KA and a boundary-element method – are integrated into a UNDE system model in this work, and their predictions for standard measurement outputs are compared with experimental data for various benchmark problems. This quantitative comparison serves as a guideline for selecting between the KA and full-wave scattering models for performing UNDE simulations. In accordance with theoretical expectations, the KA is shown to be inappropriate for modeling penetrable (inclusion-type) defects and non-specular scattering, such as diffraction from thin cracks above certain angles of incidence. A key challenge to the use of full-wave scattering methods in UNDE system models is the high computational cost incurred during simulations. Whereas the development of fast finite element methods (FEM) has inspired various applications of the FEM for ultrasound modeling in 3D heterogeneous and anisotropic media, very few applications of the BEM exist despite the progress in accelerated BEMs for elastodynamics. The BEM is highly efficient for modeling scattering from arbitrary shaped 3D defects in homogeneous isotropic media due to a reduction in the dimensionality of the scattering problem, and this potential has not been exploited for UNDE. Therefore, building on recent developments, this work proposes a fast and memory-efficient implementation of the BEM for elastic-wave scattering in UNDE applications. This method features three crucial elements that provide robustness and fast convergence. They include the use of (1) high-order discretization methods for fast convergence, (2) the combined-field integral equation (CFIE) formulation for overcoming the fictitious eigenfrequency problem, and (3) the…

Subjects/Keywords: Boundary Element Method; Elastodynamic Scattering; Fast Multipole Method; High-order BEM; Hypersingular Boundary Integral Equation; Ultrasonic Nondestructive Evaluation

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APA (6^th Edition):

Gurrala, P. (2020). Full-wave modeling of ultrasonic scattering for non-destructive evaluation. (Thesis). Iowa State University. Retrieved from https://lib.dr.iastate.edu/etd/18133

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

Chicago Manual of Style (16^th Edition):

Gurrala, Praveen. “Full-wave modeling of ultrasonic scattering for non-destructive evaluation.” 2020. Thesis, Iowa State University. Accessed January 17, 2021. https://lib.dr.iastate.edu/etd/18133.

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

MLA Handbook (7^th Edition):

Gurrala, Praveen. “Full-wave modeling of ultrasonic scattering for non-destructive evaluation.” 2020. Web. 17 Jan 2021.

Vancouver:

Gurrala P. Full-wave modeling of ultrasonic scattering for non-destructive evaluation. [Internet] [Thesis]. Iowa State University; 2020. [cited 2021 Jan 17]. Available from: https://lib.dr.iastate.edu/etd/18133.

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

Council of Science Editors:

Gurrala P. Full-wave modeling of ultrasonic scattering for non-destructive evaluation. [Thesis]. Iowa State University; 2020. Available from: https://lib.dr.iastate.edu/etd/18133

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

KTH

6. Bassili, Niclas. An evaluation of deterministic prediction of ocean waves using pressure data to assist a Wave Energy Converter.

Degree: Industrial Engineering and Management (ITM), 2020, KTH

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279600

►

Currently, existing devices for extracting electrical power from ocean waves all suffer from problems with low efficiency due to a lack of information about… (more)

▼

Currently, existing devices for extracting electrical power from ocean waves all suffer from problems with low efficiency due to a lack of information about the incoming waves in advance. The complex dynamic nonlinear characteristics of the ocean make the prediction of these incoming waves a great challenge. This paper aims to investigate a deterministic short-term wave-by-wave prediction system, that can accurately predict the wave height and timing of the incoming waves, based on measurements from a submerged pressure sensor. The complete prediction process contains three steps, namely reconstruction, assimilation, and prediction. A nonlinear Weakly Dispersive Reconstruction method (WDM) is firstly employed to accurately calculate the surface elevation from the measured pressures. Afterwards, a variational assimilation method is used to convert the time series surface elevation to a spatial wavefield, to obtain initial conditions for the prediction. Lastly, a High Order Spectral Method (HOSM) deterministically predicts the evolution of the 2D irregular wavefield based on the acquired initial conditions. To verify the performance of this proposed prediction system, tests were conducted with data from irregular sea states with varying wave parameters, generated by simulations as well as model experiments in the controlled environment of a wave tank. The results show that the surface elevation can be predicted within 5% from the reference, for a future period of about 10 seconds for wavefields commonly experienced by a wave energy converter. Based on the results, a prediction is possible, but the accuracy heavily depends on the current sea state and the chosen prediction distance.The results have been compared against similar tests made using radar data and proven to be a viable alternative for certain sea states. In conclusion, pressure measurements, as a mean to sample an ocean wavefield, is shown to be a good option when combined with nonlinear reconstruction and prediction methods to assist the power harvesting capabilities of a wave energy converter.

Nuvarande enheter för att extrahera elektrisk energi från havsvågor lider av stora problem med låg effektivitet på grund av brist på information om de inkommande vågorna. Det komplexa ickelinjära dynamiska beteendet hos havsvågor gör förutsägelsen av dem till en stor utmaning. Det här arbetet syftar till att undersöka ett deterministiskt kortsiktigt system för att förutspå våg för våg, som noggrant kan förutspå våghöjd och tidpunkt för de inkommande vågorna, baserat på mätdata från en dränkbar trycksensor. Den kompletta förutsägelseprocessen innehåller tre steg, rekonstruktion, assimilering och förutsägelse. En ickelinjär weakly dispersive reconstruction method används först för att med hög noggrannhet beräkna ythöjningen från det uppmätta trycket. Därefter, används en variational assimilation method för att konvertera en tidsserie av ythöjningen till ett rumsligt vågfält, för att erhålla initialvillkor för förutsägelsen. Slutligen används en High Order…

Subjects/Keywords: Deterministic wave prediction; Pressure sensor; Weakly dispersive reconstruction method; Time to spatial data assimilation; High-order spectral method; Determinisk vågförutsägelse; Trycksensor; Weakly dispersive reconstruction method; Time to spatial data assimilation; High-order spectral method; Engineering and Technology; Teknik och teknologier

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APA (6^th Edition):

Bassili, N. (2020). An evaluation of deterministic prediction of ocean waves using pressure data to assist a Wave Energy Converter. (Thesis). KTH. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279600

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

Chicago Manual of Style (16^th Edition):

Bassili, Niclas. “An evaluation of deterministic prediction of ocean waves using pressure data to assist a Wave Energy Converter.” 2020. Thesis, KTH. Accessed January 17, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279600.

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

MLA Handbook (7^th Edition):

Bassili, Niclas. “An evaluation of deterministic prediction of ocean waves using pressure data to assist a Wave Energy Converter.” 2020. Web. 17 Jan 2021.

Vancouver:

Bassili N. An evaluation of deterministic prediction of ocean waves using pressure data to assist a Wave Energy Converter. [Internet] [Thesis]. KTH; 2020. [cited 2021 Jan 17]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279600.

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

Council of Science Editors:

Bassili N. An evaluation of deterministic prediction of ocean waves using pressure data to assist a Wave Energy Converter. [Thesis]. KTH; 2020. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279600

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

7. Lo, Kwok Ho Marcus. A Space-Time Discontinuous Galerkin Method for Navier-Stokes with Recovery.

Degree: PhD, Aerospace Engineering, 2011, University of Michigan

URL: http://hdl.handle.net/2027.42/86313

► This thesis tells the story of two new members of a new generation of discontinuous Galerkin (DG) methods. Although DG, as a spatial discretization, has… (more)

▼ This thesis tells the story of two new members of a new generation of discontinuous Galerkin (DG) methods. Although DG, as a spatial discretization, has exhibited unparalleled success in handling advection- dominated problems on unstructured grids, DG's development in diffusion and time-marching schemes has lagged far behind in comparison. The first part of this thesis contributes to a newly introduced diffusion scheme, and the second part to an arbitrarily high-order explicit time-marching scheme. Interface-centered recovery-based DG (RDG) was first introduced by Van Leer and Nomura (2005) as a new DG discretization for diffusion. The recovery concept is attractive because it is easily understood and can be extended beyond diffusion. The idea is to recover a smooth solution across a cell interface that shares all moments with the discontinuous solutions in the two cells adjacent to that interface. RDG proves to be a scheme of fine pedigree: its order of accuracy, 3p + 1 for odd p (p is the order of the solution polynomial), and 3p + 2 for even p, is unmatched on a Cartesian grid by any existing method for diffusion. For unstructured grids, the order of accuracy is reduced to the standard p+1, but RDG still allows of much larger time steps due to smaller eigenvalues. The extension to nonlinear problems with cross-derivative terms and two-dimensional structured and unstructured grids is described. Numerical tests for a range of diffusion equations, including Navier-Stokes, conrm the high-order accuracy of RDG. Van Leer (1977) coupled spatial and temporal operators to produce an exact shift in the solution for advection at a Courant-Friedrich-Lewy (CFL) number of unity. Huynh (2005) successfully implemented this concept in the "moment scheme" (p = 1) for the Euler equations. We extend this method to arbitrarily high order, and incorporate RDG for handling diffusion. The method is currently called Hancock-Huynh discon- tinuous Galerkin (HH-DG). We have tested it on Euler problems and linear advection-diffusion problems. Advisors/Committee Members: Van Leer, Bram (committee member), Fidkowski, Krzysztof J. (committee member), Huynh, Hung T. (committee member), Katopodes, Nikolaos D. (committee member), Roe, Philip L. (committee member).

Subjects/Keywords: Computational Fluid Dynamics; Recovery-based Discontinuous Galerkin Method (RDG); Space-time Advection-diffusion; High Order; Aerospace Engineering; Engineering

2 more images…

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APA (6^th Edition):

Lo, K. H. M. (2011). A Space-Time Discontinuous Galerkin Method for Navier-Stokes with Recovery. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/86313

Chicago Manual of Style (16^th Edition):

Lo, Kwok Ho Marcus. “A Space-Time Discontinuous Galerkin Method for Navier-Stokes with Recovery.” 2011. Doctoral Dissertation, University of Michigan. Accessed January 17, 2021. http://hdl.handle.net/2027.42/86313.

MLA Handbook (7^th Edition):

Lo, Kwok Ho Marcus. “A Space-Time Discontinuous Galerkin Method for Navier-Stokes with Recovery.” 2011. Web. 17 Jan 2021.

Vancouver:

Lo KHM. A Space-Time Discontinuous Galerkin Method for Navier-Stokes with Recovery. [Internet] [Doctoral dissertation]. University of Michigan; 2011. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/2027.42/86313.

Council of Science Editors:

Lo KHM. A Space-Time Discontinuous Galerkin Method for Navier-Stokes with Recovery. [Doctoral Dissertation]. University of Michigan; 2011. Available from: http://hdl.handle.net/2027.42/86313

McMaster University

8. Duarte, Durval. A High Order Numerical Method for the Solution of the Advection Equation.

Degree: ME, 1980, McMaster University

URL: http://hdl.handle.net/11375/18538

►

Missing page 91

This report presents a numerical method which can be used to solve the advection equation (∂ɸ/∂t) + (∂[u(x,t)ɸ]/∂x) = S(x,t) where:… (more)

Subjects/Keywords: engineering physics; high order numerical method; advection equation; solution

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APA (6^th Edition):

Duarte, D. (1980). A High Order Numerical Method for the Solution of the Advection Equation. (Masters Thesis). McMaster University. Retrieved from http://hdl.handle.net/11375/18538

Chicago Manual of Style (16^th Edition):

Duarte, Durval. “A High Order Numerical Method for the Solution of the Advection Equation.” 1980. Masters Thesis, McMaster University. Accessed January 17, 2021. http://hdl.handle.net/11375/18538.

MLA Handbook (7^th Edition):

Duarte, Durval. “A High Order Numerical Method for the Solution of the Advection Equation.” 1980. Web. 17 Jan 2021.

Vancouver:

Duarte D. A High Order Numerical Method for the Solution of the Advection Equation. [Internet] [Masters thesis]. McMaster University; 1980. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/11375/18538.

Council of Science Editors:

Duarte D. A High Order Numerical Method for the Solution of the Advection Equation. [Masters Thesis]. McMaster University; 1980. Available from: http://hdl.handle.net/11375/18538

Iowa State University

9. Zhou, Ying. Development of the spectral difference method and application in the numerical investigation of the separated and transitional flows over a low-Reynolds number airfoil.

Degree: 2011, Iowa State University

URL: https://lib.dr.iastate.edu/etd/10207

► The development of the high-order accuracy spectral difference (SD) method on hexahedral mesh and its applications in aeroacoustic and aerodynamic problems are carried out in… (more)

▼ The development of the high-order accuracy spectral difference (SD) method on hexahedral mesh and its applications in aeroacoustic and aerodynamic problems are carried out in this work. Two absorbing boundary conditions, the absorbing sponge zone and the perfectly matched layer, are developed and implemented for the SD method discretizing the Euler and Navier-Stokes equations on unstructured grids. The performance of both boundary conditions is evaluated and compared with the characteristic boundary condition for a variety of benchmark problems including vortex and acoustic wave propagations. The applications of the perfectly matched layer technique in the numerical simulations of unsteady problems with complex geometries are also presented to demonstrate its capability. Numerical simulations of the low-Reynolds number (Re= 〖10〗⁴ ~ 〖10〗⁵ ) flows over a SD7003 airfoil at moderate incidences (<10y) are performed. A low-frequency convective instability is observed to dominate the spectrum near the leading edge and be responsible for the growth of the disturbance in the attached boundary layer. The characteristic frequency, the growth rate and the wave shape are investigated based on the numerical results. The growth of the low-frequency instability is not in agreement with parallel flow stability theory, nor with leading edge receptivity theory. And it has a higher growth rate than the Tollmien-Schlichting (T-S) wave. The effects of the angle-of-attack (AoA), the Reynolds number and the airfoil geometry on the low-frequency instability are investigated and discussed. The mechanisms in the breakdown process are investigated and discussed. it is observed that the breakdown of the shedding vortices starts at approximately the location with the maximum negative streamwise flow velocity. And the reverse flow in the separation region directly triggers the generation of three dimensional disturbances and the streamwise vorticities. In addition, the secondary instability which initiates the breakdown process differs in cases at different AOAs. The elliptic and hyperbolic instabilities observed in bluff-body wakes are found to occur in the breakdown process of current cases. Furthermore, the sequence of breakdown states at various incidences is found to be similar to that of the bluff-body wakes at various Reynolds numbers. A numerical investigation of passive LSB control techniques using roughness bumps on a low-Reynolds number wing is conducted as a further study. The previous case at Re=6y〖10〗⁴ and AoA=4y is used as the baseline (uncontrolled) case. In the controlled cases, roughness bumps are strategically placed near the leading edge of the wing for the purpose of improving aerodynamic performance in terms of the lift to drag ratio. The location, bump size, the number of bumps and the AoA are varied to study the effects. The pressure drag forces in the controlled cases are found to be reduced significantly when the LSB are reduced or avoided, resulting in much improved lift over drag ratio.

Subjects/Keywords: absorbing boundary condition; computational fluid dynamics; high-order method; passive flow control; separation and transition; unstructured mesh; Aerospace Engineering

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APA (6^th Edition):

Zhou, Y. (2011). Development of the spectral difference method and application in the numerical investigation of the separated and transitional flows over a low-Reynolds number airfoil. (Thesis). Iowa State University. Retrieved from https://lib.dr.iastate.edu/etd/10207

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

Chicago Manual of Style (16^th Edition):

Zhou, Ying. “Development of the spectral difference method and application in the numerical investigation of the separated and transitional flows over a low-Reynolds number airfoil.” 2011. Thesis, Iowa State University. Accessed January 17, 2021. https://lib.dr.iastate.edu/etd/10207.

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

MLA Handbook (7^th Edition):

Zhou, Ying. “Development of the spectral difference method and application in the numerical investigation of the separated and transitional flows over a low-Reynolds number airfoil.” 2011. Web. 17 Jan 2021.

Vancouver:

Zhou Y. Development of the spectral difference method and application in the numerical investigation of the separated and transitional flows over a low-Reynolds number airfoil. [Internet] [Thesis]. Iowa State University; 2011. [cited 2021 Jan 17]. Available from: https://lib.dr.iastate.edu/etd/10207.

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

Council of Science Editors:

Zhou Y. Development of the spectral difference method and application in the numerical investigation of the separated and transitional flows over a low-Reynolds number airfoil. [Thesis]. Iowa State University; 2011. Available from: https://lib.dr.iastate.edu/etd/10207

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

10. Grimich, Karim. Schémas compacts basés sur le résidu d'ordre élevé pour des écoulements compressibles instationnaires. Application à de la capture de fines échelles. : High order Residual Based Compact schemes for unsteady compressible flows. Application to scale resolving simulations.

Degree: Docteur es, Mécanique, 2013, Paris, ENSAM

URL: http://www.theses.fr/2013ENAM0033

►

Les solveurs de calcul en mécanique des fluides numérique (solveurs CFD) ont atteint leur maturité en termes de précision et d'efficacité de calcul. Toutefois, des… (more)

▼

Les solveurs de calcul en mécanique des fluides numérique (solveurs CFD) ont atteint leur maturité en termes de précision et d'efficacité de calcul. Toutefois, des progrès restent à faire pour les écoulements instationnaires surtout lorsqu'ils sont régis par de grandes structures cohérentes. Pour ces écoulements, les solveurs CFD actuels n'apportent pas de solutions assez précises à moins d'utiliser des maillages très fins. De plus, la haute précision est une caractéristique cruciale pour l'application des stratégies avancées de simulation de turbulence, comme la Simulation des Grandes Echelles (LES). Afin d'appliquer les méthodes d'ordre élevé pour les écoulements instationnaires complexes plusieurs points doivent être abordés dont la robustesse numérique et la capacité à gérer des géométries complexes.Dans cette thèse, nous étudions une famille d'approximations compactes qui offrent une grande précision non pour chaque dérivée spatiale traitée séparement mais pour le résidu r complet, c'est à dire la somme de tous les termes des équations considérées. Pour des problèmes stationnaires résolus par avancement temporelle, r est le résidu à l'état stationnaire ne comprenant que des dérivées spatiales; pour des problèmes instationnaires r comprend également la dérivée temporelle. Ce type de schémas sont appelés schémas Compacts Basés sur le Résidu (RBC). Plus précisément, nous développons des schémas RBC d'ordre élevé pour des écoulements instationnaires compressibles, et menons une étude approfondie de leurs propriétés de dissipation. Nous analysons ensuite les erreurs de dissipation et la dispersion introduites par les schémas RBC afin de quantifier leur capacité à résoudre une longueur d'onde donnée en utilisant un nombre minimal de points de maillage. Les capacités de la dissipation de RBC à drainer seulement l'énergie aux petites échelles sous-résolues sont également examinées en vue de l'application des schémas RBC pour des simulations LES implicites (ILES). Enfin, les schémas RBC sont étendus à la formulation de type volumes finis (FV) afin de gérer des géométries complexes. Une formulation FV des schémas RBC d'ordre trois préservant une précision d'ordre élevé sur des maillages irréguliers est présentée et analysée. Des applications numériques, dont la simulation d'écoulements instationnaires complexes de turbomachines régis par les équations de Navier-Stokes moyennées et des simulations ILES d'écoulements turbulents dominés par des structures cohérentes dynamiques ou en décroissance, confirment les résultats théoriques.

Computational Fluid Dynamics (CFD) solvers have reached maturity in terms of solution accuracy as well as computational efficiency. However, progress remains to be done for unsteady flows especially when governed by large, coherent structures. For these flows, current CFD solvers do not provide accurate solutions unless very fine mesh are used. Moreover, high-accuracy is a crucial feature for the application of advanced turbulence simulation strategies, like Large Eddy Simulation (LES). In…

Advisors/Committee Members: Cinnella, Paola (thesis director).

Subjects/Keywords: Schéma compact basé sur le résidu; Ordre élevé; Instationnaire; Méthode numérique; Residual-Based scheme; High-Order; Unsteady; Numérical method

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

APA (6^th Edition):

Grimich, K. (2013). Schémas compacts basés sur le résidu d'ordre élevé pour des écoulements compressibles instationnaires. Application à de la capture de fines échelles. : High order Residual Based Compact schemes for unsteady compressible flows. Application to scale resolving simulations. (Doctoral Dissertation). Paris, ENSAM. Retrieved from http://www.theses.fr/2013ENAM0033

Chicago Manual of Style (16^th Edition):

Grimich, Karim. “Schémas compacts basés sur le résidu d'ordre élevé pour des écoulements compressibles instationnaires. Application à de la capture de fines échelles. : High order Residual Based Compact schemes for unsteady compressible flows. Application to scale resolving simulations.” 2013. Doctoral Dissertation, Paris, ENSAM. Accessed January 17, 2021. http://www.theses.fr/2013ENAM0033.

MLA Handbook (7^th Edition):

Grimich, Karim. “Schémas compacts basés sur le résidu d'ordre élevé pour des écoulements compressibles instationnaires. Application à de la capture de fines échelles. : High order Residual Based Compact schemes for unsteady compressible flows. Application to scale resolving simulations.” 2013. Web. 17 Jan 2021.

Vancouver:

Grimich K. Schémas compacts basés sur le résidu d'ordre élevé pour des écoulements compressibles instationnaires. Application à de la capture de fines échelles. : High order Residual Based Compact schemes for unsteady compressible flows. Application to scale resolving simulations. [Internet] [Doctoral dissertation]. Paris, ENSAM; 2013. [cited 2021 Jan 17]. Available from: http://www.theses.fr/2013ENAM0033.

Council of Science Editors:

Grimich K. Schémas compacts basés sur le résidu d'ordre élevé pour des écoulements compressibles instationnaires. Application à de la capture de fines échelles. : High order Residual Based Compact schemes for unsteady compressible flows. Application to scale resolving simulations. [Doctoral Dissertation]. Paris, ENSAM; 2013. Available from: http://www.theses.fr/2013ENAM0033

University of Kentucky

11. Dai, Ruxin. Richardson Extrapolation-Based High Accuracy High Efficiency Computation for Partial Differential Equations.

Degree: 2014, University of Kentucky

URL: https://uknowledge.uky.edu/cs_etds/20

► In this dissertation, Richardson extrapolation and other computational techniques are used to develop a series of high accuracy high efficiency solution techniques for solving partial… (more)

Subjects/Keywords: partial differential equations; high-order compact schemes; Richardson extrapolation; multiple coarse grids; multiscale multigrid method; Numerical Analysis and Scientific Computing

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

APA (6^th Edition):

Dai, R. (2014). Richardson Extrapolation-Based High Accuracy High Efficiency Computation for Partial Differential Equations. (Doctoral Dissertation). University of Kentucky. Retrieved from https://uknowledge.uky.edu/cs_etds/20

Chicago Manual of Style (16^th Edition):

Dai, Ruxin. “Richardson Extrapolation-Based High Accuracy High Efficiency Computation for Partial Differential Equations.” 2014. Doctoral Dissertation, University of Kentucky. Accessed January 17, 2021. https://uknowledge.uky.edu/cs_etds/20.

MLA Handbook (7^th Edition):

Dai, Ruxin. “Richardson Extrapolation-Based High Accuracy High Efficiency Computation for Partial Differential Equations.” 2014. Web. 17 Jan 2021.

Vancouver:

Dai R. Richardson Extrapolation-Based High Accuracy High Efficiency Computation for Partial Differential Equations. [Internet] [Doctoral dissertation]. University of Kentucky; 2014. [cited 2021 Jan 17]. Available from: https://uknowledge.uky.edu/cs_etds/20.

Council of Science Editors:

Dai R. Richardson Extrapolation-Based High Accuracy High Efficiency Computation for Partial Differential Equations. [Doctoral Dissertation]. University of Kentucky; 2014. Available from: https://uknowledge.uky.edu/cs_etds/20

University of Kansas

12. Jia, Feilin. Towards industrial large eddy simulation using the FR/CPR method.

Degree: PhD, Aerospace Engineering, 2019, University of Kansas

URL: http://hdl.handle.net/1808/29660

► NASA’s 2030 CFD Vision calls for the development of accurate and efficient scale-resolving simulations for turbulent flow, such as large eddy simulation (LES) and direct… (more)

▼ NASA’s 2030 CFD Vision calls for the development of accurate and efficient scale-resolving simulations for turbulent flow, such as large eddy simulation (LES) and direct numerical simulation (DNS). This is primarily because the Reynolds-averaged Navier-Stokes (RANS) approach has failed to predict vortex-dominated flow involving large flow separations, e.g., flow through a jet engine or over aircraft near the edge of the flight envelope, i.e., during take-off and landing at high angles of attack. Although the DNS approach resolves all turbulence scales, it is too expensive in the foreseeable future for real world flow problems because of the disparate length and time scales in the flow. LES resolves the energetic large scales while modeling the smaller scales, so it provides a good compromise between accuracy and cost. As a result, LES is widely considered to be the method of choice for next generation CFD design tool. The major obstacle for LES is its considerable computational cost since unsteady 3D simulations need to be performed to obtain the mean flow quantities such as the drag and lift coefficients. In order to resolve the dominant scales in a turbulent flow, numerical methods used for LES should have low dissipation and dispersion errors. This means standard second order finite-volume methods are usually not accurate or efficient enough for LES applications. High-order methods (order of accuracy 2) have demonstrated their potential for LES and DNS in the past decade because of their low embedded numerical dissipation and dispersion errors. In the present study, we develop and demonstrate a recently developed high-order method, called flux reconstruction (FR) or correction procedure via reconstruction (CPR), for industrial LES. A major advantage of the FR/CPR method is its capability to handle unstructured mixed meshes, and its compactness and scalability, which is particularly desired on modern super-computers. We therefore address the following major pacing items in industrial LES in the present study: High-order methods Geometric flexibility Efficient time integration Efficient implementation on modern super computers Demonstration for real world applications Advisors/Committee Members: Taghavi, Ray (advisor), Wang, Z.J. (advisor), Taghavi, Ray (cmtemember), Wang, Z.J. (cmtemember), Farokhi, Saeed (cmtemember), Zheng, Zhongquan (cmtemember), Shontz, Suzanne M (cmtemember).

Subjects/Keywords: Aerospace engineering; computational fluid dynamics; correction procedure via reconstruction; flux reconstruction; high order method; implicit time scheme

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

APA (6^th Edition):

Jia, F. (2019). Towards industrial large eddy simulation using the FR/CPR method. (Doctoral Dissertation). University of Kansas. Retrieved from http://hdl.handle.net/1808/29660

Chicago Manual of Style (16^th Edition):

Jia, Feilin. “Towards industrial large eddy simulation using the FR/CPR method.” 2019. Doctoral Dissertation, University of Kansas. Accessed January 17, 2021. http://hdl.handle.net/1808/29660.

MLA Handbook (7^th Edition):

Jia, Feilin. “Towards industrial large eddy simulation using the FR/CPR method.” 2019. Web. 17 Jan 2021.

Vancouver:

Jia F. Towards industrial large eddy simulation using the FR/CPR method. [Internet] [Doctoral dissertation]. University of Kansas; 2019. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1808/29660.

Council of Science Editors:

Jia F. Towards industrial large eddy simulation using the FR/CPR method. [Doctoral Dissertation]. University of Kansas; 2019. Available from: http://hdl.handle.net/1808/29660

13. Paino, Paulo Celso Vieira. Análise de desempenho de um método de interfaces imersas de alta ordem.

Degree: Mestrado, Aeronaves, 2011, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/18/18148/tde-24072013-132604/ ;

►

No contexto de Dinâmica de Fluidos Computacional, métodos de simulação de objetos imersos em Malhas Cartesianas têm se mostrado vantajosos tanto em termos de Custo… (more)

▼

No contexto de Dinâmica de Fluidos Computacional, métodos de simulação de objetos imersos em Malhas Cartesianas têm se mostrado vantajosos tanto em termos de Custo Computacional quanto em termos de precisão numérica. Entretanto, a representação física de objetos imersos nesses domínios computacionais impõe a perda de validade dos esquemas de Diferenças Finitas empregados, na região das superfícies introduzidas. Este trabalho analisa um Método de Interfaces Imersas quanto ao desempenho em aplicações a esquemas de solução numérica de Alta Ordem de precisão. Através de Testes de Refinamento de Malha, é feita a apreciação da ordem de decaimento dos erros das soluções numéricas em comparação com as soluções analíticas para 2 problemas unidimensionais. O primeiro envolve a solução da Equação de Calor unidimensional sujeita a uma Condição Inicial Unitária, e o segundo relaciona-se ao cálculo das duas primeiras derivadas espaciais das funções analíticas Seno e Tangente Hiperbólica. Também é promovida uma análise de forma fragmentária do método, a fim de individualizar a contribuição dos elementos envolvidos no comportamento das soluções geradas. Os resultados obtidos indicam eventuais alterações na ordem de precisão dos esquemas de Diferenças Finitas originalmente aplicados. Esse comportamento e visto como uma dependência que o método escolhido apresenta em relação a função discretizada. Por fim, são elaboradas considerações sobre restrições de aplicabilidade do método escolhido.

In the Computational Fluid Dynamics context, methods for simulating immersed objects in Cartesian Grids have shown advantages regarding both Computational Cost and numerical precision. Nevertheless, the physical representation of immersed objects within these computational domains leads to the loss of validity of the emplyed Finite Dierence Schemes near the immersed surfaces. This work analizes a Immersed Interface Method regarding its performance in High Order Schemes applications. The error decay order for numerical solutions of two 1D problems is observed. The rst problem relates to the solution of the Heat Equation subjected to the unitary initial condition. The second relates to the computation of the rst two derivatives of analytical functions Sin and Hyperbolic Tangent. It\'s also conducted a fragmentary analysis, which is intended to identify the contribution of each element of this method to the character of the generated solution. The results indicate some eventual changes in the Order of the Finite Dierences Schemes employed. This behaviour is regarded as a dependency of this method to the nature of the discretized function. Finaly, some remarks regarding restrictions to this method\'s applicability are made.

Advisors/Committee Members: Medeiros, Marcello Augusto Faraco de.

Subjects/Keywords: CFD; CFD; Esquemas de alta ordem; High order schemes; Immersed boundaries method; Immersed interface method; Métodos de fronteiras imersas; Métodos de interfaces imersas.

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

APA (6^th Edition):

Paino, P. C. V. (2011). Análise de desempenho de um método de interfaces imersas de alta ordem. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/18/18148/tde-24072013-132604/ ;

Chicago Manual of Style (16^th Edition):

Paino, Paulo Celso Vieira. “Análise de desempenho de um método de interfaces imersas de alta ordem.” 2011. Masters Thesis, University of São Paulo. Accessed January 17, 2021. http://www.teses.usp.br/teses/disponiveis/18/18148/tde-24072013-132604/ ;.

MLA Handbook (7^th Edition):

Paino, Paulo Celso Vieira. “Análise de desempenho de um método de interfaces imersas de alta ordem.” 2011. Web. 17 Jan 2021.

Vancouver:

Paino PCV. Análise de desempenho de um método de interfaces imersas de alta ordem. [Internet] [Masters thesis]. University of São Paulo; 2011. [cited 2021 Jan 17]. Available from: http://www.teses.usp.br/teses/disponiveis/18/18148/tde-24072013-132604/ ;.

Council of Science Editors:

Paino PCV. Análise de desempenho de um método de interfaces imersas de alta ordem. [Masters Thesis]. University of São Paulo; 2011. Available from: http://www.teses.usp.br/teses/disponiveis/18/18148/tde-24072013-132604/ ;

Iowa State University

14. Chen, Kun. Boundary integral equation method for electromagnetic and elastic waves.

Degree: 2016, Iowa State University

URL: https://lib.dr.iastate.edu/etd/15679

► In this thesis, the boundary integral equation method (BIEM) is studied and applied to electromagnetic and elastic wave problems. First of all, a spectral domain… (more)

▼ In this thesis, the boundary integral equation method (BIEM) is studied and applied to electromagnetic and elastic wave problems. First of all, a spectral domain BIEM called the spectral domain approach is employed for full wave analysis of metal strip grating on grounded dielectric slab (MSG-GDS) and microstrips shielded with either perfect electric conductor (PEC) or perfect magnetic conductor (PMC) walls. The modal relations between these structures are revealed by exploring their symmetries. It is derived analytically and validated numerically that all the even and odd modes of the latter two (when they are mirror symmetric) find their correspondence in the modes of metal strip grating on grounded dielectric slab when the phase shift between adjacent two unit cells is 0 or π. Extension to non-symmetric case is also made. Several factors, including frequency, grating period, slab thickness and strip width, are further investigated for their impacts on the effective permittivity of the dominant mode of PEC/PMC shielded microstrips. It is found that the PMC shielded microstrip generally has a larger wave number than the PEC shielded microstrip. Secondly, computational aspects of the layered medim doubly periodic Green's function (LMDPGF) in matrix-friendly formulation (MFF) are investigated. The MFF for doubly periodic structures in layered medium is derived, and the singularity of the periodic Green's function when the transverse wave number equals zero in this formulation is analytically extracted. A novel approach is proposed to calculate the LMDPGF, which makes delicate use of several techniques including factorization of the Green's function, generalized pencil of function (GPOF) method and high order Taylor expansion to derive the high order asymptotic expressions, which are then evaluated by newly derived fast convergent series. This approach exhibits robustness, high accuracy and fast and high order convergence; it also allows fast frequency sweep for calculating Brillouin diagram in eigenvalue problem and for normal incidence in scattering problem. Thirdly, a high order Nyström method is developed for elastodynamic scattering that features a simple local correction scheme due to a careful choice of basis functions. A novel simple and efficient singularity subtraction scheme and a new effective near singularity subtraction scheme are proposed for performing singular and nearly singular integrals on curvilinear triangular elements. The robustness, high accuracy and high order convergence of the proposed approached are demonstrated by numerical results. Finally, the multilevel fast multipole algorithm (MLFMA) is applied to accelerate the proposed Nyström method for solving large scale problems. A Formulation that can significantly reduce the memory requirements in MLFMA is come up with. Numerical examples in frequency domain are first given to show the accuracy and efficiency of the algorithm. By solving at multiple frequencies and performing the inverse Fourier transform, time domain results are…

Subjects/Keywords: Elastodynamic scattering; Electromagnetic scattering; High order method; Integral equation method; Multilevel fast multipole algorithm; Periodic structure; Acoustics, Dynamics, and Controls; Electrical and Electronics; Electromagnetics and Photonics

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

APA (6^th Edition):

Chen, K. (2016). Boundary integral equation method for electromagnetic and elastic waves. (Thesis). Iowa State University. Retrieved from https://lib.dr.iastate.edu/etd/15679

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

Chicago Manual of Style (16^th Edition):

Chen, Kun. “Boundary integral equation method for electromagnetic and elastic waves.” 2016. Thesis, Iowa State University. Accessed January 17, 2021. https://lib.dr.iastate.edu/etd/15679.

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

MLA Handbook (7^th Edition):

Chen, Kun. “Boundary integral equation method for electromagnetic and elastic waves.” 2016. Web. 17 Jan 2021.

Vancouver:

Chen K. Boundary integral equation method for electromagnetic and elastic waves. [Internet] [Thesis]. Iowa State University; 2016. [cited 2021 Jan 17]. Available from: https://lib.dr.iastate.edu/etd/15679.

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

Council of Science Editors:

Chen K. Boundary integral equation method for electromagnetic and elastic waves. [Thesis]. Iowa State University; 2016. Available from: https://lib.dr.iastate.edu/etd/15679

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

15. LI AIDAN. A newton-type method for fluid computation.

Degree: 2005, National University of Singapore

URL: http://scholarbank.nus.edu.sg/handle/10635/14591

Subjects/Keywords: monotonical; multigrid; Newtonâ€™s method; Newton-type method; high order accuracy; incompressible flow

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

APA (6^th Edition):

AIDAN, L. (2005). A newton-type method for fluid computation. (Thesis). National University of Singapore. Retrieved from http://scholarbank.nus.edu.sg/handle/10635/14591

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

Chicago Manual of Style (16^th Edition):

AIDAN, LI. “A newton-type method for fluid computation.” 2005. Thesis, National University of Singapore. Accessed January 17, 2021. http://scholarbank.nus.edu.sg/handle/10635/14591.

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

MLA Handbook (7^th Edition):

AIDAN, LI. “A newton-type method for fluid computation.” 2005. Web. 17 Jan 2021.

Vancouver:

AIDAN L. A newton-type method for fluid computation. [Internet] [Thesis]. National University of Singapore; 2005. [cited 2021 Jan 17]. Available from: http://scholarbank.nus.edu.sg/handle/10635/14591.

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

Council of Science Editors:

AIDAN L. A newton-type method for fluid computation. [Thesis]. National University of Singapore; 2005. Available from: http://scholarbank.nus.edu.sg/handle/10635/14591

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

University of Kentucky

16. Guernsey, Bryan James. A LOCALLY CORRECTED NYSTRM METHOD FOR SURFACE INTEGRAL EQUATIONS: AN OBJECT ORIENTED APPROACH.

Degree: 2007, University of Kentucky

URL: https://uknowledge.uky.edu/gradschool_theses/460

► Classically, researchers in Computational Physics and specifically in Computational Electromagnetics have sought to find numerical solutions to complex physical problems. Several techniques have been developed… (more)

Subjects/Keywords: Electromagnetics; Integral Equations; Nystrm Method; High Order Solution Method; Object Oriented Software

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

APA (6^th Edition):

Guernsey, B. J. (2007). A LOCALLY CORRECTED NYSTRM METHOD FOR SURFACE INTEGRAL EQUATIONS: AN OBJECT ORIENTED APPROACH. (Masters Thesis). University of Kentucky. Retrieved from https://uknowledge.uky.edu/gradschool_theses/460

Chicago Manual of Style (16^th Edition):

Guernsey, Bryan James. “A LOCALLY CORRECTED NYSTRM METHOD FOR SURFACE INTEGRAL EQUATIONS: AN OBJECT ORIENTED APPROACH.” 2007. Masters Thesis, University of Kentucky. Accessed January 17, 2021. https://uknowledge.uky.edu/gradschool_theses/460.

MLA Handbook (7^th Edition):

Guernsey, Bryan James. “A LOCALLY CORRECTED NYSTRM METHOD FOR SURFACE INTEGRAL EQUATIONS: AN OBJECT ORIENTED APPROACH.” 2007. Web. 17 Jan 2021.

Vancouver:

Guernsey BJ. A LOCALLY CORRECTED NYSTRM METHOD FOR SURFACE INTEGRAL EQUATIONS: AN OBJECT ORIENTED APPROACH. [Internet] [Masters thesis]. University of Kentucky; 2007. [cited 2021 Jan 17]. Available from: https://uknowledge.uky.edu/gradschool_theses/460.

Council of Science Editors:

Guernsey BJ. A LOCALLY CORRECTED NYSTRM METHOD FOR SURFACE INTEGRAL EQUATIONS: AN OBJECT ORIENTED APPROACH. [Masters Thesis]. University of Kentucky; 2007. Available from: https://uknowledge.uky.edu/gradschool_theses/460

University of Manitoba

17. Gholami, Reza. Novel surface-volume-surface electric field integral equations for electromagnetic analysis of 3-D metal-dielectric objects and H-matrix strategies for their fast direct solution.

Degree: Electrical and Computer Engineering, 2019, University of Manitoba

URL: http://hdl.handle.net/1993/34403

► The hierarchical (H)-matrix acceleration method plays important role in electromagnetic analysis of large-scale problems. This thesis is about fast direct solution of 3-D full-wave scattering… (more)

▼ The hierarchical (H)-matrix acceleration method plays important role in electromagnetic analysis of large-scale problems. This thesis is about fast direct solution of 3-D full-wave scattering and radiation problems with H-matrix acceleration of the method of moments (MoM) for the novel surface-volume-surface electric field integral equation (SVS-EFIE) and the Locally Corrected Nystrom (LCN) method for traditional magnetic field integral equation (MFIE). Two new formulations of the SVS-EFIE are proposed. First, new SVS-EFIE formulation is developed for the scattering and radiation problems on metal-dielectric composite objects with arbitrary number of regions situated in free space. Second, new SVS-EFIE formulation is developed for scattering and radiation problems on dielectric-dielectric composite objects situated in multilayered medium. The proposed SVS-EFIE formulations introduce independent surface electric current density on the boundary of each region. Thus, in the new formulations, the scatterer regions can be meshed independently according to their local material properties. This improves the flexibility and efficiency of the proposed formulations in the analysis of both multiscale and large-scale composite structures. An H-matrix based fast direct solution strategies are proposed for acceleration of the MoM solution of the new SVS-EFIE formulations. The method is largely insensitive to the poor conditioning of the MoM matrix equation. The required theory for applying H-matrices to the new formulations as well as the construction of the block H-matrices pertinent to MoM discretization of the composite SVS-EFIE is described in detail. Numerical validation shows that the proposed methods have a wide-range of applications and generate accurate results using only the small fraction of memory and total CPU time needed by conventional MoM solution of the SVS-EFIE. Fast error-controlled direct solution of the traditional integral equations for scattering problems on metal objects with H-matrices is also pioneered in this work. The proposed strategy for acceleration of the higher-order LCN method with H-matrices exhibits O(h^p) error behavior in the fast direct solution of the scattering problems on smooth metal objects with characteristic mesh elements size h and order of solution approximation p. Advisors/Committee Members: Okhmatovski, Vladimir (Electrical and Computer Engineering), Mojabi, Puyan (Electrical and Computer Engineering).

Subjects/Keywords: Electromagnetics; Integral Equations; Computational Electromagnetics; Numerical Analysis; Fast Algorithms; Method of Moments; Boundary Element Method; Electromagnetic Analysis; Multilayered Media; Single source integral equations; Composite objects; Higher-Order; high-order solution; Error controllable solution

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APA (6^th Edition):

Gholami, R. (2019). Novel surface-volume-surface electric field integral equations for electromagnetic analysis of 3-D metal-dielectric objects and H-matrix strategies for their fast direct solution. (Thesis). University of Manitoba. Retrieved from http://hdl.handle.net/1993/34403

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

Chicago Manual of Style (16^th Edition):

Gholami, Reza. “Novel surface-volume-surface electric field integral equations for electromagnetic analysis of 3-D metal-dielectric objects and H-matrix strategies for their fast direct solution.” 2019. Thesis, University of Manitoba. Accessed January 17, 2021. http://hdl.handle.net/1993/34403.

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

MLA Handbook (7^th Edition):

Gholami, Reza. “Novel surface-volume-surface electric field integral equations for electromagnetic analysis of 3-D metal-dielectric objects and H-matrix strategies for their fast direct solution.” 2019. Web. 17 Jan 2021.

Vancouver:

Gholami R. Novel surface-volume-surface electric field integral equations for electromagnetic analysis of 3-D metal-dielectric objects and H-matrix strategies for their fast direct solution. [Internet] [Thesis]. University of Manitoba; 2019. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1993/34403.

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

Council of Science Editors:

Gholami R. Novel surface-volume-surface electric field integral equations for electromagnetic analysis of 3-D metal-dielectric objects and H-matrix strategies for their fast direct solution. [Thesis]. University of Manitoba; 2019. Available from: http://hdl.handle.net/1993/34403

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

University of Michigan

18. Suzuki, Yoshifumi. Discontinuous Galerkin Methods for Extended Hydrodynamics.

Degree: PhD, Aerospace Engineering and Scientific Computing, 2008, University of Michigan

URL: http://hdl.handle.net/2027.42/58411

► This dissertation presents a step towards high-order methods for continuum-transition flows. In order to achieve maximum accuracy and efficiency for numerical methods on a distorted… (more)

▼ This dissertation presents a step towards high-order methods for continuum-transition flows. In order to achieve maximum accuracy and efficiency for numerical methods on a distorted mesh, it is desirable that both governing equations and corresponding numerical methods are in some sense compact. We argue our preference for a physical model described solely by first-order partial differential equations called hyperbolic-relaxation equations, and, among various numerical methods, for the discontinuous Galerkin method. Hyperbolic-relaxation equations can be generated as moments of the Boltzmann equation and can describe continuum-transition flows. Two challenging properties of hyperbolic-relaxation equations are the presence of a stiff source term, which drives the system towards equilibrium, and the accompanying change of eigenstructure. The first issue can be solved by an implicit treatment of the source term. To cope with the second difficulty, we develop a space-time discontinuous Galerkin method, based on Huynh’s “upwind moment scheme.” It is called the DG(1)–Hancock method. The DG(1)–Hancock method for one- and two-dimensional meshes is described, and Fourier analyses for both linear advection and linear hyperbolic-relaxation equations are conducted. The analyses show that the DG(1)–Hancock method is not only accurate but efficient in terms of turnaround time in comparison to other semiand fully discrete finite-volume and discontinuous Galerkin methods. Numerical tests confirm the analyses, and also show the properties are preserved for nonlinear equations; the efficiency is superior by an order of magnitude. Subsequently, discontinuous Galerkin and finite-volume spatial discretizations are applied to more practical equations, in particular, to the set of 10-moment equations, which are gas dynamics equations that include a full pressure/temperature tensor among the flow variables. Results for flow around a micro-airfoil are compared to experimental data and to solutions obtained with a Navier–Stokes code, and with particle-based methods. While numerical solutions in the continuum regime for both the 10-moment and Navier–Stokes equations are similar, clear differences are found in the continuum-transition regime, especially near the stagnation point, where the Navier–Stokes code, even when implemented with wall-slip, overestimates the density. Advisors/Committee Members: Van Leer, Bram (committee member), Huynh, Hung T. (committee member), Larsen, Edward W. (committee member), Powell, Kenneth G. (committee member), Roe, Philip L. (committee member).

Subjects/Keywords: Discontinuous Galerkin Method; Extended Hydrodynamics; High Order Method; Hyperbolic-relaxation Equation; Hancock Method; Space-time Discretization Method; Aerospace Engineering; Engineering

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

APA (6^th Edition):

Suzuki, Y. (2008). Discontinuous Galerkin Methods for Extended Hydrodynamics. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/58411

Chicago Manual of Style (16^th Edition):

Suzuki, Yoshifumi. “Discontinuous Galerkin Methods for Extended Hydrodynamics.” 2008. Doctoral Dissertation, University of Michigan. Accessed January 17, 2021. http://hdl.handle.net/2027.42/58411.

MLA Handbook (7^th Edition):

Suzuki, Yoshifumi. “Discontinuous Galerkin Methods for Extended Hydrodynamics.” 2008. Web. 17 Jan 2021.

Vancouver:

Suzuki Y. Discontinuous Galerkin Methods for Extended Hydrodynamics. [Internet] [Doctoral dissertation]. University of Michigan; 2008. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/2027.42/58411.

Council of Science Editors:

Suzuki Y. Discontinuous Galerkin Methods for Extended Hydrodynamics. [Doctoral Dissertation]. University of Michigan; 2008. Available from: http://hdl.handle.net/2027.42/58411

19. Busatto, Alcides Dallanora. An optimization-based method for high order gradient calculation on unstructured meshes.

Degree: PhD, Computational Engineering, 2012, Mississippi State University

URL: http://sun.library.msstate.edu/ETD-db/theses/available/etd-07062012-095544/ ;

► A new implicit and compact optimization-based method is presented for high order derivative calculation for finite-volume numerical method on unstructured meshes. Highorder approaches to… (more)

▼ A new implicit and compact optimization-based method is presented for high order derivative calculation for finite-volume numerical method on unstructured meshes. Highorder approaches to gradient calculation are often based on variants of the Least-Squares (L-S) method, an explicit method that requires a stencil large enough to accommodate the necessary variable information to calculate the derivatives. The new scheme proposed here is applicable for an arbitrary order of accuracy (demonstrated here up to 3rd order), and uses just the first level of face neighbors to compute all derivatives, thus reducing stencil size and avoiding stiffness in the calculation matrix. Preliminary results for a static variable field example and solution of a simple scalar transport (advection) equation show that the proposed method is able to deliver numerical accuracy equivalent to (or better than) the nominal order of accuracy for both 2nd and 3rd order schemes in the presence of a smoothly distributed variable field (i.e., in the absence of discontinuities). This new Optimization-based Gradient REconstruction (herein denoted OGRE) scheme produces, for the simple scalar transport test case, lower error and demands less computational time (for a given level of required precision) for a 3rd order scheme when compared to an equivalent L-S approach on a two-dimensional framework. For three-dimensional simulations, where the L-S scheme fails to obtain convergence without the help of limiters, the new scheme obtains stable convergence and also produces lower error solution when compared to a third order MUSCL scheme. Furthermore, spectral analysis of results from the advection equation shows that the new scheme is better able to accurately resolve high wave number modes, which demonstrates its potential to better solve problems presenting a wide spectrum of wavelengths, for example unsteady turbulent flow simulations. Advisors/Committee Members: J. Mark Janus (committee member), Seongjai Kim (committee member), Edward A. Luke (committee member), D. Keith Walters (chair).

Subjects/Keywords: high order schemes; gradient reconstruction; finite volume method

…BASED METHOD FOR HIGH ORDER GRADIENT CALCULATION ON UNSTRUCTURED MESHES . . . . . . . . 4… …28 31 32 36 38 38 42 46 3. A 3D OPTIMIZATION-BASED METHOD FOR HIGH ORDER GRADIENT… …CHAPTER 2 A 2D OPTIMIZATION-BASED METHOD FOR HIGH ORDER GRADIENT CALCULATION ON UNSTRUCTURED… …computationally efficient. This paper presents a new method for high-order gradient calculation on… …initial multidimensional approach. The high-order k-exact method was developed by Barth and…

10 more images…

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

APA (6^th Edition):

Busatto, A. D. (2012). An optimization-based method for high order gradient calculation on unstructured meshes. (Doctoral Dissertation). Mississippi State University. Retrieved from http://sun.library.msstate.edu/ETD-db/theses/available/etd-07062012-095544/ ;

Chicago Manual of Style (16^th Edition):

Busatto, Alcides Dallanora. “An optimization-based method for high order gradient calculation on unstructured meshes.” 2012. Doctoral Dissertation, Mississippi State University. Accessed January 17, 2021. http://sun.library.msstate.edu/ETD-db/theses/available/etd-07062012-095544/ ;.

MLA Handbook (7^th Edition):

Busatto, Alcides Dallanora. “An optimization-based method for high order gradient calculation on unstructured meshes.” 2012. Web. 17 Jan 2021.

Vancouver:

Busatto AD. An optimization-based method for high order gradient calculation on unstructured meshes. [Internet] [Doctoral dissertation]. Mississippi State University; 2012. [cited 2021 Jan 17]. Available from: http://sun.library.msstate.edu/ETD-db/theses/available/etd-07062012-095544/ ;.

Council of Science Editors:

Busatto AD. An optimization-based method for high order gradient calculation on unstructured meshes. [Doctoral Dissertation]. Mississippi State University; 2012. Available from: http://sun.library.msstate.edu/ETD-db/theses/available/etd-07062012-095544/ ;

20. Saito, Olga Harumi. Esquema numérico com reconstrução mínimos quadrados de alta ordem em malhas não-estruturadas para a formulação euleriana do transporte de partículas.

Degree: PhD, Matemática Aplicada, 2008, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/45/45132/tde-15042008-165404/ ;

►

O estudo do transporte de partículas tem uma importância fundamental em diversas áreas de pesquisas como, por exemplo, na formação de gelo em uma aeronave… (more)

▼

O estudo do transporte de partículas tem uma importância fundamental em diversas áreas de pesquisas como, por exemplo, na formação de gelo em uma aeronave pois pode afetar a sua sustentação e estabilidade. Tamanha é a preocupação com a segurança de vôo que diversos estudos têm sido realizados, resultando em códigos computacionais como o LEWICE nos Estados Unidos, TRAJICE no Reino Unido, ONERA na França e CANICE no Canadá. No Brasil, um dos estudo é feito pela EMBRAER em parceria com algumas instituições. O objetivo deste trabalho é desenvolver um algoritmo que possa ser empregado na trajetória das partículas, utilizando uma formulação euleriana que elimina a dificuldade da semeadura de partículas específica da formulação lagrangiana na determinação da fração de volume da partícula. O método empregado é dos volumes finitos em malhas não-estruturadas cuja principal chave está na reconstrução mínimos quadrados de alta ordem com restrição nos contornos. O desenvolvimento do trabalho engloba 3 etapas: definição da geometria e geração das malhas; utilização de um solver para o tratamento do escoamento do ar e obtenção do campo de velocidade; implementação e utilização do esquema numérico com reconstrução mínimos quadrados de alta ordem para simular o cálculo da fração de volume com imposição de condições limites apropriadas no contorno do corpo. Os resultados dos testes realizados mostram que o esquema numérico com reconstrução mínimos quadrados pode ser empregado na resolução de equações que apresentam uma região de descontinuidade, como é o caso da região de sombra, reduzindo a largura da banda de difusão numérica e overshoots.

The particle transport study has a fundamental importance in diverse research area like in the icing accretion on an aircraft because that can affect its sustentation and stability. The concern is so big that many researches have been carried through, resulting in computational codes like the LEWICE in the United States, TRAJICE in the United Kingdom, ONERA in France and CANICE in Canada. In Brazil, one of the study has been made by the EMBRAER with some institutes. The goal of this work is to develop an algorithm that can be used in the particles trajectory study, using an Eulerian method that eliminates the difficulty particle sowing, particular of the Lagrangian method, in the determination of the droplet fraction volume. This is made by the finite volume method on unstructured meshes whose main key is the high order reconstruction with restriction on the boundary. The development of the work involves 3 stages: geometry definition and mesh generation; using code for the treatment of the air flow and obtained flow velocity; use of the high order numerical scheme least square reconstruction to simulate the droplet fraction volume result with imposition of appropriate limit conditions in the body contour. The realized simulations shown that Least Square method can be used in problem resolution that present descontinuos region like is shadow region…

Advisors/Committee Members: Santos, Luis Carlos de Castro.

Subjects/Keywords: advecção-difusão; advection-diffusion; Eulerian formulation; finite volume method; formulação euleriana; high order reconstruction; malha não-estruturada; reconstrução de alta ordem; unstructured grid; volumes finitos

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

APA (6^th Edition):

Saito, O. H. (2008). Esquema numérico com reconstrução mínimos quadrados de alta ordem em malhas não-estruturadas para a formulação euleriana do transporte de partículas. (Doctoral Dissertation). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/45/45132/tde-15042008-165404/ ;

Chicago Manual of Style (16^th Edition):

Saito, Olga Harumi. “Esquema numérico com reconstrução mínimos quadrados de alta ordem em malhas não-estruturadas para a formulação euleriana do transporte de partículas.” 2008. Doctoral Dissertation, University of São Paulo. Accessed January 17, 2021. http://www.teses.usp.br/teses/disponiveis/45/45132/tde-15042008-165404/ ;.

MLA Handbook (7^th Edition):

Saito, Olga Harumi. “Esquema numérico com reconstrução mínimos quadrados de alta ordem em malhas não-estruturadas para a formulação euleriana do transporte de partículas.” 2008. Web. 17 Jan 2021.

Vancouver:

Saito OH. Esquema numérico com reconstrução mínimos quadrados de alta ordem em malhas não-estruturadas para a formulação euleriana do transporte de partículas. [Internet] [Doctoral dissertation]. University of São Paulo; 2008. [cited 2021 Jan 17]. Available from: http://www.teses.usp.br/teses/disponiveis/45/45132/tde-15042008-165404/ ;.

Council of Science Editors:

Saito OH. Esquema numérico com reconstrução mínimos quadrados de alta ordem em malhas não-estruturadas para a formulação euleriana do transporte de partículas. [Doctoral Dissertation]. University of São Paulo; 2008. Available from: http://www.teses.usp.br/teses/disponiveis/45/45132/tde-15042008-165404/ ;

Univerzitet u Beogradu

21. Krneta, Aleksandra J., 1989-. Функције базиса ултра високог реда и сингуларне функције базиса у анализи аксијално симетричних металних структура.

Degree: Elektrotehnički fakultet, 2018, Univerzitet u Beogradu

URL: https://fedorabg.bg.ac.rs/fedora/get/o:18346/bdef:Content/get

►

Електротехника и рачунарство-Електромагнетика, антене и микроталаси / Electrical and Computer Engineering-Electromagnetics, antennas and microwave

Рад електронских уређаја и система, као што су мобилна телефонија, телевизија,… (more)

▼

Електротехника и рачунарство-Електромагнетика, антене и микроталаси / Electrical and Computer Engineering-Electromagnetics, antennas and microwave

Рад електронских уређаја и система, као што су мобилна телефонија, телевизија, рачунари, сателитски комуникациони системи, радарски системи и многи други, базира се на електромагнетским феноменима који су предмет изучавања теорије електромагнетских поља. За разумевање начина рада ових система и за њихово пројектовање потребно је извршити електромагнетску (ЕМ) анализу. У већини случајева ЕМ анализа се спроводи применом неке од метода нумеричке електромагнетике. Једна од најчешће коришћених нумеричких метода за ЕМ анализу је метода момената примењена на решавање површинских интегралних једначина. Применом ове методе струје расподељене по граничним површима домена апроксимирају се сумом познатих функција базиса помножених непознатим коефицијентима, а површинске интегралне једначине трансформишу се у систем линеарних једначина чијим се решавањем одређују ти непознати коефицијенти. Ова метода се унапређује већ више десетина година, а актуелни технички и технолошки трендови постављају сталне захтеве за повећањем тачности и ефикасности ЕМ моделовања, за анализом све већих и комплекснијих структура, које укључују све ситније детаље, као и за проширењем опсега учестаности, идући од веома ниских до веома високих учестаности. Повећање тачности, ефикасности и домена примене ове методе могу се остварити 1) имплементацијом комплекснијих елемената за прецизно моделовање геометрије проблема, 2) рачунањем елемената системске матрице са великом тачношћу, и 3) коришћењем софистицираних функција базиса за апроксимацију струје. Циљ ове дисертације је развој нове методе, базиране на методи момената, за анализу аксијално симетричних металних структура коришћењем егзактног језгра интегралне једначине електричног поља и применом све три горе поменуте технике. За прецизно геометријско моделовање проблема коришћени су зарубљени конуси, а струја је иницијално апроксимирана модификованим функцијама базиса вишег реда. Импедансни интеграли, који представљају елементе системске матрице су, уз помоћ симетрије, редуковани са четвороструких на троструке интеграле, при чему прве две интеграције одговарају интегралима потенцијала. Свака од три интеграције у оквиру импедансних интеграла показује сингуларно или квази-сингуларно понашање у одређеним ситуацијама. У том случају се ови интеграли неефикасно рачунају директном применом Гаус-Лежандрове интеграционе формуле, па су за њихово рачунање предложене нове техникe поништавања сингуларитета. Техника поништавања сингуларитета подразумева примену погодно одабране смене којом се интегранд трансформише у споро променљиву функцију па се интеграл затим може ефикасно израчунати нумерички, применом Гаус-Лежандрове интеграционе формуле. Након одабира оптималних смена осмишљене су једноставне формуле за одређивање потребног броја тачака интеграције за остваривање жељене тачности. Рачунање импедансних интеграла са великом тачношћу (до машинске прецизности), као што је…

Advisors/Committee Members: Kolundžija, Branko, 1958-.

Subjects/Keywords: axially symmetric metallic structures; edge effect; exact kernel; impedance integral; integral equation; method of moments; singularity cancellation; ultra high order basis functions

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

APA (6^th Edition):

Krneta, Aleksandra J., 1. (2018). Функције базиса ултра високог реда и сингуларне функције базиса у анализи аксијално симетричних металних структура. (Thesis). Univerzitet u Beogradu. Retrieved from https://fedorabg.bg.ac.rs/fedora/get/o:18346/bdef:Content/get

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

Chicago Manual of Style (16^th Edition):

Krneta, Aleksandra J., 1989-. “Функције базиса ултра високог реда и сингуларне функције базиса у анализи аксијално симетричних металних структура.” 2018. Thesis, Univerzitet u Beogradu. Accessed January 17, 2021. https://fedorabg.bg.ac.rs/fedora/get/o:18346/bdef:Content/get.

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

MLA Handbook (7^th Edition):

Krneta, Aleksandra J., 1989-. “Функције базиса ултра високог реда и сингуларне функције базиса у анализи аксијално симетричних металних структура.” 2018. Web. 17 Jan 2021.

Vancouver:

Krneta, Aleksandra J. 1. Функције базиса ултра високог реда и сингуларне функције базиса у анализи аксијално симетричних металних структура. [Internet] [Thesis]. Univerzitet u Beogradu; 2018. [cited 2021 Jan 17]. Available from: https://fedorabg.bg.ac.rs/fedora/get/o:18346/bdef:Content/get.

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

Council of Science Editors:

Krneta, Aleksandra J. 1. Функције базиса ултра високог реда и сингуларне функције базиса у анализи аксијално симетричних металних структура. [Thesis]. Univerzitet u Beogradu; 2018. Available from: https://fedorabg.bg.ac.rs/fedora/get/o:18346/bdef:Content/get

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

22. LIU YANGYANG. DEVELOPMENT OF HIGH-ORDER FINITE VOLUME METHODS ON UNSTRUCTURED GRIDS AND THEIR APPLICATIONS.

Degree: 2020, National University of Singapore

URL: https://scholarbank.nus.edu.sg/handle/10635/166577

Subjects/Keywords: high-order; unstructured grids; finite volume method; compressible; incompressible; PEEB limiter

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

APA (6^th Edition):

YANGYANG, L. (2020). DEVELOPMENT OF HIGH-ORDER FINITE VOLUME METHODS ON UNSTRUCTURED GRIDS AND THEIR APPLICATIONS. (Thesis). National University of Singapore. Retrieved from https://scholarbank.nus.edu.sg/handle/10635/166577

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

Chicago Manual of Style (16^th Edition):

YANGYANG, LIU. “DEVELOPMENT OF HIGH-ORDER FINITE VOLUME METHODS ON UNSTRUCTURED GRIDS AND THEIR APPLICATIONS.” 2020. Thesis, National University of Singapore. Accessed January 17, 2021. https://scholarbank.nus.edu.sg/handle/10635/166577.

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

MLA Handbook (7^th Edition):

YANGYANG, LIU. “DEVELOPMENT OF HIGH-ORDER FINITE VOLUME METHODS ON UNSTRUCTURED GRIDS AND THEIR APPLICATIONS.” 2020. Web. 17 Jan 2021.

Vancouver:

YANGYANG L. DEVELOPMENT OF HIGH-ORDER FINITE VOLUME METHODS ON UNSTRUCTURED GRIDS AND THEIR APPLICATIONS. [Internet] [Thesis]. National University of Singapore; 2020. [cited 2021 Jan 17]. Available from: https://scholarbank.nus.edu.sg/handle/10635/166577.

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

Council of Science Editors:

YANGYANG L. DEVELOPMENT OF HIGH-ORDER FINITE VOLUME METHODS ON UNSTRUCTURED GRIDS AND THEIR APPLICATIONS. [Thesis]. National University of Singapore; 2020. Available from: https://scholarbank.nus.edu.sg/handle/10635/166577

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

23. Zhou, Cheng. Adaptive High-Order Discretization of the Reynolds-Averaged Navier-Stokes(RANS) Equations.

Degree: PhD, Aerospace Engineering, 2016, University of Kansas

URL: http://hdl.handle.net/1808/24139

► The use of high-order methods to compute turbulent flows governed by the Reynolds- averaged Navier-Stokes (RANS) equations is an active research topic in the compu-… (more)

▼ The use of high-order methods to compute turbulent flows governed by the Reynolds- averaged Navier-Stokes (RANS) equations is an active research topic in the compu- tational fluid dynamics (CFD) community. However, it is well known that high-order methods for the non-smooth turbulence modeling equations are difficult to converge to the steady-state because of the numerical stiffness. The objective of this work is to de- velop a robust and efficient high-order discretization that can simulate turbulent flows governed by the Reynolds-Averaged Navier-Stokes equations, which involves the de- velopment of high-order space discretization of robust turbulence modeling equations, the improvement of time integration strategy, and the application of effective mesh adaptation methods. In the present study, correction procedure via reconstruction (CPR) high-order dis- cretization is developed to solve the Reynolds-averaged Navier-Stokes (RANS) equa- tions with the modified Spalart and Allmaras (SA) model. In this model, the non- dimensional length scale depends on the distance to the nearest wall. To compute the distance of each solution point in the domain to the nearest curved polynomial wall boundaries, the CPR high-order discretization is extended to solve the Eikonal equa- tion. On the other hand, to improve time integration strategy for the simulation of turbulent flows, the present work carried out a comparative study of several implicit time integration schemes to determine which is the most efficient, robust and general scheme. Additionally, an adjoint-based adaptive mesh refinement method is utilized to minimize the output error. Numerical results show that, to achieve a certain level of accuracy, the adaptive CPR discretization of the RANS equations with the SA model saves orders of magnitude in terms of number of degrees of freedom comparing to the numerical results of uniform mesh refinement, when applied to the simulations of turbulent flows. Advisors/Committee Members: Wang, Z.J. (advisor), Farokhi, Saeed (cmtemember), Taghavi, Ray (cmtemember), Tu, Xuemin (cmtemember), Zheng, Zhongquan Charlie (cmtemember).

Subjects/Keywords: Aerospace engineering; Mathematics; Adaptive; CFD; CPR; High-order method; RANS

…34, 76]. In the present method, a dual-consistent high-order CPR is utilized to… …turbulent flows using the CPR method. • Demonstrated the importance of the high-order CPR method… …use the high-order CPR method to solve the equation. For more complicated flow geometries… …1.2 Background and Objective High-order CFD methods have received considerable attention… …cost than low order methods. The use of high-order methods to compute turbulent flows…

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APA (6^th Edition):

Zhou, C. (2016). Adaptive High-Order Discretization of the Reynolds-Averaged Navier-Stokes(RANS) Equations. (Doctoral Dissertation). University of Kansas. Retrieved from http://hdl.handle.net/1808/24139

Chicago Manual of Style (16^th Edition):

Zhou, Cheng. “Adaptive High-Order Discretization of the Reynolds-Averaged Navier-Stokes(RANS) Equations.” 2016. Doctoral Dissertation, University of Kansas. Accessed January 17, 2021. http://hdl.handle.net/1808/24139.

MLA Handbook (7^th Edition):

Zhou, Cheng. “Adaptive High-Order Discretization of the Reynolds-Averaged Navier-Stokes(RANS) Equations.” 2016. Web. 17 Jan 2021.

Vancouver:

Zhou C. Adaptive High-Order Discretization of the Reynolds-Averaged Navier-Stokes(RANS) Equations. [Internet] [Doctoral dissertation]. University of Kansas; 2016. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1808/24139.

Council of Science Editors:

Zhou C. Adaptive High-Order Discretization of the Reynolds-Averaged Navier-Stokes(RANS) Equations. [Doctoral Dissertation]. University of Kansas; 2016. Available from: http://hdl.handle.net/1808/24139

24. Albert Willian Faria. Modelagem por elementos finitos de placas compostas dotadas de sensores e atuadores piezoelétricos : implementação computacional e avaliação numérica.

Degree: 2006, Federal University of Uberlândia

URL: http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1136 ; http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1137 ; http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1138

►

Esta dissertação apresenta uma metodologia baseada no Método dos Elementos Finitos (MEF) para a modelagem de estruturas compostas laminadas do tipo viga e placa dotadas… (more)

▼

Esta dissertação apresenta uma metodologia baseada no Método dos Elementos Finitos (MEF) para a modelagem de estruturas compostas laminadas do tipo viga e placa dotadas de sensores e atuadores piezoelétricos. Os conceitos fundamentais e o desenvolvimento teórico são apresentados, seguidos de simulações numéricas realizadas em ambiente MATLAB para a modelagem dessas estruturas. O elemento finito implementado é do tipo Serendipity, tem forma retangular, oito pontos nodais, onze graus de liberdade mecânicos por nó e oito graus de liberdade elétricos por interface de camada piezoelétrica. Os efeitos da temperatura são desprezados. É empregada uma Teoria Mista baseada no uso de camada equivalente única para representação do campo de deslocamentos mecânicos e em múltiplas camadas para o campo elétrico. A aproximação do campo de deslocamentos mecânicos utiliza duas teorias distintas: a Teoria da Deformação de Terceira Ordem (HSDT) e a Teoria da Deformação Cisalhante de Primeira Ordem (FSDT). As teorias em estudo são implementadas computacionalmente e confrontadas através da realização de simulações numéricas e os resultados são comparados com os disponíveis na literatura. Nestas simulações, alguns aspectos relevantes do comportamento estático e dinâmico sob vibração livre de vigas e placas retangulares dotadas de sensores e atuadores piezoelétricos são avaliados, tais como deflexão, freqüências naturais e potenciais elétricos. São discutidas as vantagens e desvantagens da utilização de cada uma dessas teorias na modelagem de estruturas inteligentes.

This Dissertation presents a methodology based on the Finite Element method for the modeling of laminated composite beams and plates containing piezoelectric sensors and actuators. The fundamental concepts and the theoretical developments are presented, followed by a number of numerical simulations performed in MATLAB environment. The finite element used is a Serendipity-type element with rectangular shape, eight nodes, eleven mechanical degrees-of-freedom per node and eight electrical degrees-of-freedom per interface of piezoelectric layer. Temperature effects are neglected. A Mixed Theory is adopted, which uses a single equivalent layer for discretization of the mechanical displacement field and a layerwise representation of the electrical field. For the approximation of the mechanical displacements, two different theories are used, namely: the Higher-order Shear Deformation Theory (HSDT) and the First-order Shear Deformation Theory (FSDT). Both theories are numerically implemented and used in a number numerical simulations whose results are available in the literature. In these simulations, some relevant aspects of the static and dynamic behavior of beams and rectangular plates containing piezoelectric sensors and actuators are appraised. The main advantages and drawbacks of the theories, as applied to the modeling of intelligent composite structures are pointed-out.

Advisors/Committee Members: Jesiel Cunha, Paulo de Tarso Rocha de Mendonça, Raquel Santini Leandro Rade, Domingos Alves Rade.

Subjects/Keywords: piezoeletricidade; Teoria da deformação cisalhante de primeira/terceira ordem; Teoria mista; Estruturas compostas; Estruturas inteligentes; Elementos finitos; ENGENHARIA MECANICA; Vibração; Intelligent structures; Finite element method; Composite materials; Mixed theory; First-order/ high-order shear deformation theory; Piezoelectricity; Método dos elementos finitos

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

APA (6^th Edition):

Faria, A. W. (2006). Modelagem por elementos finitos de placas compostas dotadas de sensores e atuadores piezoelétricos : implementação computacional e avaliação numérica. (Thesis). Federal University of Uberlândia. Retrieved from http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1136 ; http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1137 ; http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1138

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

Chicago Manual of Style (16^th Edition):

Faria, Albert Willian. “Modelagem por elementos finitos de placas compostas dotadas de sensores e atuadores piezoelétricos : implementação computacional e avaliação numérica.” 2006. Thesis, Federal University of Uberlândia. Accessed January 17, 2021. http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1136 ; http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1137 ; http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1138.

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

MLA Handbook (7^th Edition):

Faria, Albert Willian. “Modelagem por elementos finitos de placas compostas dotadas de sensores e atuadores piezoelétricos : implementação computacional e avaliação numérica.” 2006. Web. 17 Jan 2021.

Vancouver:

Faria AW. Modelagem por elementos finitos de placas compostas dotadas de sensores e atuadores piezoelétricos : implementação computacional e avaliação numérica. [Internet] [Thesis]. Federal University of Uberlândia; 2006. [cited 2021 Jan 17]. Available from: http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1136 ; http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1137 ; http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1138.

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

Council of Science Editors:

Faria AW. Modelagem por elementos finitos de placas compostas dotadas de sensores e atuadores piezoelétricos : implementação computacional e avaliação numérica. [Thesis]. Federal University of Uberlândia; 2006. Available from: http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1136 ; http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1137 ; http://www.bdtd.ufu.br//tde_busca/arquivo.php?codArquivo=1138

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

25. Gobé, Alexis. Méthodes Galerkin discontinues pour la simulation de problèmes multiéchelles en nanophotonique et applications au piégeage de la lumière dans des cellules solaires : Discontinuous Galerkin methods for the simulation of multiscale nanophotonic problems with application to light trapping in solar cells.

Degree: Docteur es, Mathématiques, 2020, Université Côte d'Azur

URL: http://www.theses.fr/2020COAZ4011

►

L’objectif de cette thèse est l’étude numérique du piégeage de la lumière dans des cellules solaires nanostructurées. Le changement climatique est devenu une problématique majeure… (more)

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L’objectif de cette thèse est l’étude numérique du piégeage de la lumière dans des cellules solaires nanostructurées. Le changement climatique est devenu une problématique majeure nécessitant une transition énergétique à court terme. Dans ce contexte, l'énergie solaire semble être une source énergétique idéale. Cette ressource est à la fois scalable à l’échelle planétaire et écologique. Afin de maximiser sa pénétration, des travaux visant à augmenter la quantité de lumière absorbée et à réduire les coûts liés à la conception des cellules sont nécessaires. Le piégeage de la lumière est une stratégie qui permet d’atteindre ces deux objectifs. Son principe consiste à utiliser des texturations nanométriques afin de focaliser la lumière dans les couches de semi-conducteur absorbantes. Dans ce travail, la méthode de Galerkine Discontinue en Domaine Temporel (DGTD) est introduite. Deux développements méthodologiques majeurs, permettant de mieux prendre en compte les caractéristiques des cellules solaires, sont présentés. Tout d'abord, l’utilisation d’un ordre d’approximation local est proposé , basé sur une stratégie de répartition particulière de l’ordre. Le deuxième développement est l’utilisation de maillage hybride mixant ses élements hexahédriques structurés et tétrahédriques non structurés. Des cas réalistes de cellules solaires issus de la littérature et de collaborations avec des physiciens du domaine du photovoltaïque permettent d'illustrer l' apport de ces développements. Un cas d’optimisation inverse de réseau de diffraction dans une cellule solaire est également présenté en couplant le solveur numérique avec un algorithme d’optimisation bayésienne. De plus, une étude approfondie des performances du solveur a également été réalisée avec des modifications méthodologiques pour contrer les problèmes de répartition de charge. Enfin, une méthode plus prospective, la méthode Multiéchelle Hybride-Mixte (MHM) spécialisée dans la résolution de problème très fortement multiéchelle est introduite. Un schéma en temps multiéchelle est présenté et sa stabilité prouvée.

The objective of this thesis is the numerical study of light trapping in nanostructured solar cells. Climate change has become a major issue requiring a short-term energy transition. In this context, solar energy seems to be an ideal energy source. This resource is both globally scalable and environmentally friendly. In order to maximize its penetration, it is needed to increase the amount of light absorbed and reduce the costs associated with cell design. Light trapping is a strategy that achieves both of these objectives. The principle is to use nanometric textures to focus the light in the absorbing semiconductor layers. In this work, the Discontinuous Galerkin Time-Domain (DGTD) method is introduced. Two major methodological developments are presented, allowing to better take into account the characteristics of solar cells. First, the use of a local approximation order is proposed, based on a particular order distribution strategy. The second development…

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

Subjects/Keywords: Équations de Maxwell; Méthode de Galerkine discontinue; Matériaux dispersifs; Photovoltaique; Piégeage de la lumière; Nanophotonique; Maillage hybride; Maillage non conforme; Méthode d’ordre élevé; Méthode multi échelle; Optimisation; Calcul haute performance; Maxwell’s equations; Discontinuous Galerkin method; Dispersive materials; Photovoltaics; Light trapping; Nanophotonics; Hybrid mesh; Non conform mesh; High order method; Multiscale method; Optimization; High performance computing

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

APA (6^th Edition):

Gobé, A. (2020). Méthodes Galerkin discontinues pour la simulation de problèmes multiéchelles en nanophotonique et applications au piégeage de la lumière dans des cellules solaires : Discontinuous Galerkin methods for the simulation of multiscale nanophotonic problems with application to light trapping in solar cells. (Doctoral Dissertation). Université Côte d'Azur. Retrieved from http://www.theses.fr/2020COAZ4011

Chicago Manual of Style (16^th Edition):

Gobé, Alexis. “Méthodes Galerkin discontinues pour la simulation de problèmes multiéchelles en nanophotonique et applications au piégeage de la lumière dans des cellules solaires : Discontinuous Galerkin methods for the simulation of multiscale nanophotonic problems with application to light trapping in solar cells.” 2020. Doctoral Dissertation, Université Côte d'Azur. Accessed January 17, 2021. http://www.theses.fr/2020COAZ4011.

MLA Handbook (7^th Edition):

Gobé, Alexis. “Méthodes Galerkin discontinues pour la simulation de problèmes multiéchelles en nanophotonique et applications au piégeage de la lumière dans des cellules solaires : Discontinuous Galerkin methods for the simulation of multiscale nanophotonic problems with application to light trapping in solar cells.” 2020. Web. 17 Jan 2021.

Vancouver:

Gobé A. Méthodes Galerkin discontinues pour la simulation de problèmes multiéchelles en nanophotonique et applications au piégeage de la lumière dans des cellules solaires : Discontinuous Galerkin methods for the simulation of multiscale nanophotonic problems with application to light trapping in solar cells. [Internet] [Doctoral dissertation]. Université Côte d'Azur; 2020. [cited 2021 Jan 17]. Available from: http://www.theses.fr/2020COAZ4011.

Council of Science Editors:

Gobé A. Méthodes Galerkin discontinues pour la simulation de problèmes multiéchelles en nanophotonique et applications au piégeage de la lumière dans des cellules solaires : Discontinuous Galerkin methods for the simulation of multiscale nanophotonic problems with application to light trapping in solar cells. [Doctoral Dissertation]. Université Côte d'Azur; 2020. Available from: http://www.theses.fr/2020COAZ4011

26. Bello-Maldonado, Pedro David. Low-order finite element preconditioner for spectral element pressure solver in Navier-Stokes equations.

Degree: MS, Computer Science, 2016, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/95408

► High-order spectral element methods (SEM) while very accurate for computational fluid dynamics (CFD) simulations can be prohibitively expensive for meshes with difficult geometries. Controlling the… (more)

Subjects/Keywords: Finite element method (FEM); Spectral element method (SEM); Preconditioner; Computational fluid dynamics (CFD); Low-order methods; High-order methods

…level, the SEM is a high-order method closely related to the Finite Element Method (FEM… …treated with the Spectral Element Method first proposed by Patera in [3]. At a high… …spectral method and pseudo-spectral method are also important and cited here. 2.1 Low-Order… …method based on a low-order finite-difference approximation to the spectral operator on the… …element method that uses compatible velocity (order N ) and pressure (order N −2…

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APA (6^th Edition):

Bello-Maldonado, P. D. (2016). Low-order finite element preconditioner for spectral element pressure solver in Navier-Stokes equations. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/95408

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

Chicago Manual of Style (16^th Edition):

Bello-Maldonado, Pedro David. “Low-order finite element preconditioner for spectral element pressure solver in Navier-Stokes equations.” 2016. Thesis, University of Illinois – Urbana-Champaign. Accessed January 17, 2021. http://hdl.handle.net/2142/95408.

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

MLA Handbook (7^th Edition):

Bello-Maldonado, Pedro David. “Low-order finite element preconditioner for spectral element pressure solver in Navier-Stokes equations.” 2016. Web. 17 Jan 2021.

Vancouver:

Bello-Maldonado PD. Low-order finite element preconditioner for spectral element pressure solver in Navier-Stokes equations. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2016. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/2142/95408.

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

Council of Science Editors:

Bello-Maldonado PD. Low-order finite element preconditioner for spectral element pressure solver in Navier-Stokes equations. [Thesis]. University of Illinois – Urbana-Champaign; 2016. Available from: http://hdl.handle.net/2142/95408

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

27. Sanjaya, Devina. Towards Automated, Metric-Conforming, Mesh Optimization For High-Order, Finite-Element Methods.

Degree: PhD, Aerospace Engineering, 2019, University of Michigan

URL: http://hdl.handle.net/2027.42/151619

► High-resolution flow simulations are becoming important for increasingly many engineering applications. While high-resolution simulations give us the accuracy needed for engineering purposes, they generally demand… (more)

Subjects/Keywords: computational fluid dyanmics; metric-based mesh adaptation; high-order mesh; high-order metric field; high-order, metric-conforming mesh; warped-element refinement method; Aerospace Engineering; Engineering

…High-order mesh generation . . . . . . . . . . . . . . . . . . . 3.4.1 Local mesh… …4.3 Warping high-order mesh elements . . . . . . . . 4.4 Significance of high-order geometry… …5.3.3 High-order MOESS (HOMES) . . . . 5.4 The need for higher-order metric field… …88 88 91 92 93 101 104 111 112 117 120 VI. High-Order, Metric-Conforming Meshes for One… …single, high-order mesh element . . . . 6.2 Predicting an output of interest…

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

APA (6^th Edition):

Sanjaya, D. (2019). Towards Automated, Metric-Conforming, Mesh Optimization For High-Order, Finite-Element Methods. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/151619

Chicago Manual of Style (16^th Edition):

Sanjaya, Devina. “Towards Automated, Metric-Conforming, Mesh Optimization For High-Order, Finite-Element Methods.” 2019. Doctoral Dissertation, University of Michigan. Accessed January 17, 2021. http://hdl.handle.net/2027.42/151619.

MLA Handbook (7^th Edition):

Sanjaya, Devina. “Towards Automated, Metric-Conforming, Mesh Optimization For High-Order, Finite-Element Methods.” 2019. Web. 17 Jan 2021.

Vancouver:

Sanjaya D. Towards Automated, Metric-Conforming, Mesh Optimization For High-Order, Finite-Element Methods. [Internet] [Doctoral dissertation]. University of Michigan; 2019. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/2027.42/151619.

Council of Science Editors:

Sanjaya D. Towards Automated, Metric-Conforming, Mesh Optimization For High-Order, Finite-Element Methods. [Doctoral Dissertation]. University of Michigan; 2019. Available from: http://hdl.handle.net/2027.42/151619

28. Durochat, Clément. Méthode de type Galerkin discontinu en maillages multi-éléments pour la résolution numérique des équations de Maxwell instationnaires : High order non-conforming multi-element Discontinuous Galerkin method for time-domain electromagnetics.

Degree: Docteur es, Mathématiques, 2013, Nice

URL: http://www.theses.fr/2013NICE4005

►

Cette thèse porte sur l’étude d’une méthode de type Galerkin discontinu en domaine temporel (GDDT), afin de résoudre numériquement les équations de Maxwell instationnaires sur… (more)

▼

Cette thèse porte sur l’étude d’une méthode de type Galerkin discontinu en domaine temporel (GDDT), afin de résoudre numériquement les équations de Maxwell instationnaires sur des maillages hybrides tétraédriques/hexaédriques en 3D (triangulaires/quadrangulaires en 2D) et non-conformes, que l’on note méthode GDDT-PpQk. Comme dans différents travaux déjà réalisés sur plusieurs méthodes hybrides (par exemple des combinaisons entre des méthodes Volumes Finis et Différences Finies, Éléments Finis et Différences Finies, etc.), notre objectif principal est de mailler des objets ayant une géométrie complexe à l’aide de tétraèdres, pour obtenir une précision optimale, et de mailler le reste du domaine (le vide environnant) à l’aide d’hexaèdres impliquant un gain en terme de mémoire et de temps de calcul. Dans la méthode GDDT considérée, nous utilisons des schémas de discrétisation spatiale basés sur une interpolation polynomiale nodale, d’ordre arbitraire, pour approximer le champ électromagnétique. Nous utilisons un flux centré pour approcher les intégrales de surface et un schéma d’intégration en temps de type saute-mouton d’ordre deux ou d’ordre quatre. Après avoir introduit le contexte historique et physique des équations de Maxwell, nous présentons les étapes détaillées de la méthode GDDT-PpQk. Nous réalisons ensuite une analyse de stabilité L2 théorique, en montrant que cette méthode conserve une énergie discrète et en exhibant une condition suffisante de stabilité de type CFL sur le pas de temps, ainsi que l’analyse de convergence en h (théorique également), conduisant à un estimateur d’erreur a-priori. Ensuite, nous menons une étude numérique complète en 2D (ondes TMz), pour différents cas tests, des maillages hybrides et non-conformes, et pour des milieux de propagation homogènes ou hétérogènes. Nous faisons enfin de même pour la mise en oeuvre en 3D, avec des simulations réalistes, comme par exemple la propagation d’une onde électromagnétique dans un modèle hétérogène de tête humaine. Nous montrons alors la cohérence entre les résultats mathématiques et numériques de cette méthode GDDT-PpQk, ainsi que ses apports en termes de précision et de temps de calcul.

This thesis is concerned with the study of a Discontinuous Galerkin Time-Domain method (DGTD), for the numerical resolution of the unsteady Maxwell equations on hybrid tetrahedral/hexahedral in 3D (triangular/quadrangular in 2D) and non-conforming meshes, denoted by DGTD-PpQk method. Like in several studies on various hybrid time domain methods (such as a combination of Finite Volume with Finite Difference methods, or Finite Element with Finite Difference, etc.), our general objective is to mesh objects with complex geometry by tetrahedra for high precision and mesh the surrounding space by square elements for simplicity and speed. In the discretization scheme of the DGTD method considered here, the electromagnetic field components are approximated by a high order nodal polynomial, using a centered approximation for the surface integrals. Time integration of…

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

Subjects/Keywords: Équations de Maxwell; Méthode de type Galerkin discontinu; Méthode hybride; Multiéléments; Maillage non-conforme; Stabilité; Convergence; Précision d’ordre élevé; Temps de calcul; Maxwell equations; Discontinuous Galerkin method; Hybrid method; Multi-element; Nonconforming mesh; Stability; Convergence; High order accuracy; CPU time; 510

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

APA (6^th Edition):

Durochat, C. (2013). Méthode de type Galerkin discontinu en maillages multi-éléments pour la résolution numérique des équations de Maxwell instationnaires : High order non-conforming multi-element Discontinuous Galerkin method for time-domain electromagnetics. (Doctoral Dissertation). Nice. Retrieved from http://www.theses.fr/2013NICE4005

Chicago Manual of Style (16^th Edition):

Durochat, Clément. “Méthode de type Galerkin discontinu en maillages multi-éléments pour la résolution numérique des équations de Maxwell instationnaires : High order non-conforming multi-element Discontinuous Galerkin method for time-domain electromagnetics.” 2013. Doctoral Dissertation, Nice. Accessed January 17, 2021. http://www.theses.fr/2013NICE4005.

MLA Handbook (7^th Edition):

Durochat, Clément. “Méthode de type Galerkin discontinu en maillages multi-éléments pour la résolution numérique des équations de Maxwell instationnaires : High order non-conforming multi-element Discontinuous Galerkin method for time-domain electromagnetics.” 2013. Web. 17 Jan 2021.

Vancouver:

Durochat C. Méthode de type Galerkin discontinu en maillages multi-éléments pour la résolution numérique des équations de Maxwell instationnaires : High order non-conforming multi-element Discontinuous Galerkin method for time-domain electromagnetics. [Internet] [Doctoral dissertation]. Nice; 2013. [cited 2021 Jan 17]. Available from: http://www.theses.fr/2013NICE4005.

Council of Science Editors:

Durochat C. Méthode de type Galerkin discontinu en maillages multi-éléments pour la résolution numérique des équations de Maxwell instationnaires : High order non-conforming multi-element Discontinuous Galerkin method for time-domain electromagnetics. [Doctoral Dissertation]. Nice; 2013. Available from: http://www.theses.fr/2013NICE4005

29. Loy, Kak Choon. Efficient Semi-Implicit Time-Stepping Schemes for Incompressible Flows .

Degree: 2017, University of Ottawa

URL: http://hdl.handle.net/10393/36442

► The development of numerical methods for the incompressible Navier-Stokes equations received much attention in the past 50 years. Finite element methods emerged given their robustness… (more)

Subjects/Keywords: time-stepping; Navier-Stokes equations; finite element method; Taylor-Hood elements; high-order; 2D/3D unsteady flows; semi-implicit; grad-div stabilization; defect correction; sequential regularization method; artificial-compressibility; flow around the cylinder; lid-driven cavity

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

APA (6^th Edition):

Loy, K. C. (2017). Efficient Semi-Implicit Time-Stepping Schemes for Incompressible Flows . (Thesis). University of Ottawa. Retrieved from http://hdl.handle.net/10393/36442

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

Chicago Manual of Style (16^th Edition):

Loy, Kak Choon. “Efficient Semi-Implicit Time-Stepping Schemes for Incompressible Flows .” 2017. Thesis, University of Ottawa. Accessed January 17, 2021. http://hdl.handle.net/10393/36442.

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

MLA Handbook (7^th Edition):

Loy, Kak Choon. “Efficient Semi-Implicit Time-Stepping Schemes for Incompressible Flows .” 2017. Web. 17 Jan 2021.

Vancouver:

Loy KC. Efficient Semi-Implicit Time-Stepping Schemes for Incompressible Flows . [Internet] [Thesis]. University of Ottawa; 2017. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/10393/36442.

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

Council of Science Editors:

Loy KC. Efficient Semi-Implicit Time-Stepping Schemes for Incompressible Flows . [Thesis]. University of Ottawa; 2017. Available from: http://hdl.handle.net/10393/36442

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

Louisiana State University

30. Piao, Cheng. Wood laminated composite poles.

Degree: PhD, 2003, Louisiana State University

URL: etd-0305103-101059 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1521

► Wood composite poles are new engineered products with polygonal shapes and bonded with synthetic resins. The poles have multiple advantages over the solid wood poles… (more)

▼ Wood composite poles are new engineered products with polygonal shapes and bonded with synthetic resins. The poles have multiple advantages over the solid wood poles and are a promising solid pole substitute in power transmission, telecommunication, and cable TV services. The use of composite poles may reduce the cost both in materials and manipulation, and facilitate installation and treatment. It is necessary to evaluate the factors that affect their properties and construct theoretical and analytical models to analyze these properties. Experiments were conducted to investigate strip thickness and number of strips’ (NOS) effects on the flexural properties and shear stress of wood composite poles. Small-scale (diameter = 7.6 cm (3 in), length = 1.16 m (48 in)) and full size poles (diameter = 10.2 cm (4 in), length = 6 m (20 ft) were manufactured for this purpose. Four strip thickness levels and three number-of-strip levels for the small-scale poles, and three thickness levels and two number-of-strip levels for full-size poles were chosen as experimental variables. The lumber was cut into strips, which were bonded with synthetic resin in molds, and the resulting poles were evaluated in a cantilever test. Results show that the effects of strip thickness were negative on glue-line shear and positive on the shear at poles’ clamped ends. But thickness had little effects on maximum bending stress of the small-scale poles and Young’s modulus of both full- and small-scale poles. With the increase of NOS, Young’s modulus of poles was increased. NOS had little effects on the maximum bending stress and glue-line shear of small-scale poles. A theoretical analysis was carried out to study the deflection and stress of composite poles. Governing differential equations were derived from high-order differential equations based on the principle of minimum potential energy theorem. Transverse shear and body forces were included in the model. Investigations were also carried out to find glue-line effects on the stress and deflection of composite poles. An analytical solution is modeled with the finite element analysis using ANSYS. Both theoretical and analytical solutions were verified by the experimental data.

Subjects/Keywords: variational method; energy method; finite element; analytical; theoretical; poles; composites; glue-line; glue-layer; high-order governing differential equation

Record Details Similar Records Cite « Share

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

APA (6^th Edition):

Piao, C. (2003). Wood laminated composite poles. (Doctoral Dissertation). Louisiana State University. Retrieved from etd-0305103-101059 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1521

Chicago Manual of Style (16^th Edition):

Piao, Cheng. “Wood laminated composite poles.” 2003. Doctoral Dissertation, Louisiana State University. Accessed January 17, 2021. etd-0305103-101059 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1521.

MLA Handbook (7^th Edition):

Piao, Cheng. “Wood laminated composite poles.” 2003. Web. 17 Jan 2021.

Vancouver:

Piao C. Wood laminated composite poles. [Internet] [Doctoral dissertation]. Louisiana State University; 2003. [cited 2021 Jan 17]. Available from: etd-0305103-101059 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1521.

Council of Science Editors:

Piao C. Wood laminated composite poles. [Doctoral Dissertation]. Louisiana State University; 2003. Available from: etd-0305103-101059 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1521

Open Access Theses and Dissertations