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Wagenaar, Thomas (author)While physicsinformed neural networks have been shown to accurately solve a wide range of fluid dynamics problems, their effectivity on highly compressible flows is so far limited. In particular, they struggle with transonic and supersonic problems that involve discontinuities such as shocks. While there have been multiple efforts to alleviate...master thesis 2023
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Dekker, Joey (author)Advection is at the heart of fluid dynamics and is responsible for many interesting phenomena. Unfortunately, it is also the source of the nonlinearity of fluid dynamics. As such, its numerical treatment is challenging and often suboptimal. One way to more effectively deal with advection is by using a Lagrangian formulation instead of the...master thesis 2022
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van Schie, Sebastiaan (author)This thesis poses a new geometric formulation for compressible Euler flows. A partial decomposition of this model into Roe variables is applied; this turns mass density, momentum and kinetic energy into product quantities of the Roe variables. Lie derivative advection operators of weak forms constructed with this decomposed model naturally...master thesis 2021
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Bertocchi, F. (author), Rohde, M. (author), Kloosterman, J.L. (author)The core of a Liquid Metal Fast Breeder Reactor (LMFBR) consists of cylindrical fuel rods that are wrapped by a helicoidallywound wire spacer to enhance mixing and to prevent damage by fretting. It is known that the liquid metal close to the rod is forced to follow the wires, and that liquid metal further away from the rod crosses the wires ...journal article 2019
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Verheij, Lennart (author)In turbomachinery optimisation problems, run time is often a critical factor due to high dimensionality of the design search space. This work explores the use of the multifidelity method to speed up an aerodynamic optimisation algorithm applied to axial compressor blades. A rotor blade is optimised in a twostage blade geometry for maximum...master thesis 2017
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Bruell, G. (author), EhrnstrĂ¶m, Mats (author), Geyer, A. (author), Pei, Long (author)We show that for a large class of evolutionary nonlinear and nonlocal partial differential equations, symmetry of solutions implies very restrictive properties of the solutions and symmetry axes. These restrictions are formulated in terms of three principles, based on the structure of the equations. The first principle covers equations that...journal article 2017
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Janssen, S.R. (author)Double degree. Supervision of the thesis also at: Faculty Applied Mathematics, Department Numerical Analysis, Programme M.Sc. Applied Mathematics. Structurepreserving discretization techniques preserve fundamental structure of operators and operands found in partial differential equations. Classical discretization techniques sometimes neglect...master thesis 2016
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Zhang, Y. (author)Based on the recently developed mimetic spectral element method, we propose an effective numerical scheme for solving threedimensional periodic incompressible Euler flows, which spatially preserves mass, kinetic energy and helicity. Preserving multiple integral invariants numerically will significantly contribute to the stability and accuracy...master thesis 2016
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Jaeschke, A.M. (author)Computeraided design (CAD) and finite element analysis (FEA) tools are extensively used in industrial design processes. The idea of isogeometric analysis (IGA) is to bring those worlds closer together. Combining them significantly increases the efficiency of the design and development processes. The general idea of the IGA approach is to use...master thesis 2015
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Van Oers, A.M. (author)A DGFEM discretization has been developed for the Hamiltonian dynamics of stratified incompressible linear fluid flow. The developed discretization can handle the numerical challenges posed by wave attractors: the three dimensionality of the domain, the focusing of wave energy and the incompressibility of the flow. The discretization is...master thesis 2015
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Carpentieri, G. (author)This thesis presents a shape optimization framework for problems that are encountered routinely in Aerodynamic Design. The nature of the framework is numerical. Its focus is wide as different aspects of the shape optimization practice are treated, e.g., the solution of the flow equations, the sensitivity analysis and the parameterization of the...doctoral thesis 2009
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Witteveen, J.A.S. (author)A second order front tracking method is developed for solving the Euler equations of inviscid fluid dynamics numerically. Front tracking methods are usually limited to first order accuracy, since they are based on a piecewise constant approximation of the solution. Here the second order convergence is achieved by building a piecewise linear...conference paper 2009
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Desideri, J.A. (author), Dervieux, A. (author)This lecture is devoted to the presentation of two particular "hierarchical" approaches to numerical shape optimization in aerodynamics design: 1) multilevel parametric shape optimization algorithms; 2) additive preconditioners. The first approach is inspired from the classical geometrical multigrid method, except that here the geometrical...conference paper 2006
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Titarev, V.A. (author), Romenski, E.I. (author), Toro, E.F. (author)Numerical methods for solving nonlinear systems of hyperbolic conservation laws via finite volume methods or discontinuous Galerkin finite element methods require, as the building block, a monotone numerical flux. The simplest approach for providing a monotone numerical utilizes a symmetric stencil and does not explicitly make use of wave...conference paper 2006
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Pollul, B. (author)We consider a NewtonKrylov approach for discretized compressible Euler equations. A good preconditioner in the Krylov subspace method is essential for obtaining an efficient solver in such an approach. In this paper we compare pointblockGaussSeidel, pointblockILU and pointblockSPAI preconditioners. It turns out that the SPAI method is...conference paper 2006
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Pesch, L. (author), Van der Vegt, J.J.W. (author)A method to numerically solve the Euler equations for fluids with general equations of state is presented. It is based on a formulation solving the conservation equations for either pressure primitive variables or entropy variables, instead of the commonly used conservation variables. We use a spacetime discontinuous Galerkin finiteelement...conference paper 2006
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Huang, X. (author), Ma, Z. (author), Zhang, X. (author)This paper outlines the method of a blockstructured adaptive mesh refinement (AMR) and its application to the computation of noise radiation from a realistic engine exhaust geometry with flow. The computational model described allows acoustic waves, propagating inside the bypass duct of a generic aircraft engine, to be admitted into a...conference paper 2006
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Bernacki, M. (author), Piperno, S. (author)We present in this paper a timedomain Discontinuous Galerkin dissipationfree method for the transient solution of the threedimensional linearized Euler equations around a steadystate solution. In the general context of a nonuniform supporting flow, we prove, using the wellknown symmetrization of Euler equations, that some aeroacoustic...conference paper 2006
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 Koren, B. (author), Michielsen, P.F.M. (author), Kars, J.W. (author), Wesseling, P. (author) journal article 1995
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Westland, J. (author), Hounjet, M.H.L. (author)In comparison with Euler methods unsteady inviscid transonic full potential methods are known to suffer from limitations with respect to the modeling of shock waves. In this paper unsteady 2D and 3D full potential methods are extended with the Clebsch variable model. This model represents exactly the shockgenerated entropy and vorticity. The...report 1993
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