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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 64 for “"convection-diffusion"”.
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Layer-adapted meshes for convection-diffusion problems
… perturbation problems - in particular stationary convection-dominated convection-diffusion problems. More precisely it is devoted to the construction and analysis of layer-adapted meshes underlying these numerical methods. An early important contribution towards the optimization of numerical …
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Adaptive refinement methods for singularly perturbed convection-diffusion problems
Contains fulltext : 145683.pdf (Publisher’s version ) (Open Access)
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Control volume unstructured mesh procedure for convection-diffusion solidification processes
The research work presented herein addresses the unstructured mesh problem in finite volume (FV) or control volume (CV) method used in numerical simulations. The modelling work conducted is in context of solidification for casting processes. The control volume-unstructured mesh (CV-UM) method can …
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On numerical methods for direct and inverse convection-diffusion problems
De thesis bestaat uit 3 delen. In het eerste deel komen oplossingsmethoden van “directe” of “voorwaartse” randwaardeproblemen aan bod. In hoofdstuk 2 wordt een niet-lineair convectie-diffusievraagstuk beschouwd. Dit vraagstuk modeleert de verspreiding van contaminanten in de ondergrond ten gevolge …
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Moving Mesh Finite Element Method for Time Dependent Convection-Diffusion Problems
… This is especially true for singularly perturbed convection-diffusion problems. In the presence of vanishing molecular diffusivity, MM- FEM may not suffice. The numerical method may exhibit under-diffusive properties and other methods need to be integrated into the classic Galerkin formulation. We …
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Stabilized Finite Element Methods for Feedback Control of Convection Diffusion Equations
… quadratic regulator (LQR) control problems for convection diffusion equations. The motivation for this effort comes from the observation that when linearization is applied to fluid flow control problems the resulting equations have the form of a convection diffusion equation. This effort is …
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Domain Decomposition Methods for Convection-Diffusion-Reaction Equations with Finite Volume Discretizations
In this dissertation, fast solvers for the convection-diffusion-reaction (CDR) model with the finite volume discretization are studied. Both overlapping and non-overlapping domain decom- position (DD) preconditioning methods are considered. With overlapping DD preconditioners, we work on a time …
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On the false-diffusion problem in the numerical modelling of convection-diffusion processes
… conservation and the elimination of 'false-diffusion', a new flow-oriented finite-volume numerical scheme was devised and applied to several test cases in order to evaluate its performance. The novel approach in formulating the new CUPID* scheme (for Corner UPw^nDing) underlines the idea of …
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Unstructured Nodal Discontinuous Galerkin Method for Convection-Diffusion Equations Applied to Neutral Fluids and Plasmas
… the DG method has been extensively applied to convection-diffusion problems. In this dissertation, a numerical package, texttt{PHORCE}, is introduced to solve a number of convection-diffusion problems in neutral fluids and plasmas. Unstructured grids are used in order to randomize grid errors, …
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Nonlinear model reduction for uncertainty quantification in large-scale inverse problems : application to nonlinear convection-diffusion-reaction equation
… nonlinear combustion problem governed by a convection-diffusion-reaction PDE with up to 3 input parameters. The reduced basis approximation developed for this problem is up to 50, 000 times faster to solve than the original high-fidelity finite element model with an average relative error in …
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Efficient reduced-basis approximation of scalar nonlinear time-dependent convection-diffusion problems, and extension to compressible flow problems
… method is applied to nonlinear time-dependent convection-diffusion parameterized partial differential equations (PDEs). A proper orthogonal decomposition (POD) procedure is used for the construction of reduced-basis approximation for the field variables. In the presence of highly nonlinear …
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Nodal Methods for Problems in Fluid Mechanics and Neutron Transport (navier-Stokes Equation, Boussinesq, Lid-Driven Cavity, Natural Thermal Convection, Diffusion Synthetic Acceleration)
… recently for the numerical solution of neutron diffusion and neutron transport problems.
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Power plant carbon dioxide emission quantification with plume modeling
… mathematical and physical models, such as a convection-diffusion plume model and a Gaussian plume model. The convection-diffusion model is based on the convection-diffusion partial differential equation describing mass transfer in diffusion and convection fields. The Gaussian model is a …
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Fast Solvers for Models of Fluid Flow with Spectral Elements
… product based discretizations of the steady convection-diffusion and the linearized Navier-Stokes equations. The method is based on iterative substructuring where fast diagonalization is used to efficiently eliminate the interior degrees of freedom and subsidiary subdomain solves. We …
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Long-term variation in cosmic-ray modulation
… o the equation can be derived, namely the Convection-Diffusion and th Force-Field approximations. These approximations were implemented t account for heliospheric modulation only. Utilizing the Force-Fiel approximations, Usoskin et al. (2011) calculated the modulatio potentials between 1936 …
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A Nodal Approach to Arbitrary Geometries, and Adaptive Mesh Refinement for the Nodal Method
… Application of this modified implementation to convection-diffusion problems proves that the coarse mesh efficiency of the nodal method can be maintained by taking advantage of ""off the shelf"" advanced solver technology."
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High Resolution Time-Limiter Schemes for Conservation Laws
… schemes to multi-dimensional problems and convection-diffusion problems. The numerical results for one- and two-dimensional problems confirm that the L-DIRK3 scheme generate high resolution and less oscillatory solutions under large time step. Particularly, the L-DIRK3 scheme shows a clear …
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Recycling Bi-Lanczos Algorithms: BiCG, CGS, and BiCGSTAB
… and the BiCGSTAB algorithms. Experiments on a convection-diffusion problem give promising results.
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The Solution of a Parabolic Partial Differential Equation via Domain Decomposition: The Synthesis of Asymptotic and Numerical Analysis
… efficient solution of a time dependent reaction convection diffusion equation with small parameter on the diffusion term will be presented. The method is based on a domain decomposition that is dictated by singular perturbation analysis. The analysis is used to determine regions where certain …
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