Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 82 for “"Advection-diffusion"”.
-
Entropic criteria for computational models of advection-diffusion equations
… methods for the estimation of parameters within advection-diffusion equations (ADEs) often overlook the entropic contribution of the discretization, i.e.number of particles, within associated numerical methods. Many times, the gain in accuracyof a highly discretized numerical model is outweighed …
-
Numerical methods for advection-diffusion-reaction equations and medical applications
… a relaxation procedure for numerically solving advection-diffusion-reaction equations, and secondly, a medical application. Concerning the first topic, we extend the applicability of the Cattaneo relaxation approach to reformulate time-dependent advection-diffusion-reaction equations, that may …
-
MODEL-BASED LEARNING AND CONTROL OF ADVECTION-DIFFUSION TRANSPORT USING MOBILE ROBOTS
… a fluid medium is mathematically modeled by the Advection-Diffusion (AD) Partial Differential Equation (PDE). Despite versatility, rigorous derivation, and powerful descriptive nature, the AD-PDE has seldom been used in its general form for the solution of the CPT problem due to high …
-
On the development of preconditioning the advection diffusion operators with spectral element discretization
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-05-01
-
A fast characteristic finite difference method for fractional advection-diffusion equations with non-linear reaction.
… approximation discritizing the fractional advection-diffusion equation unconditionally stable. We add an additional non-linear, Lipschitz continuous term to account for reactions and we solve the advection-diffusion equation utilizing fast Toeplitz matrix-vector multiplication. We then …
-
Parameter Estimation in the Advection Diffusion Reaction Model With Mean Occupancy Time and Boundary Flux Approaches
In this dissertation, we examine an advection diffusion model for insects inhabiting a spatially heterogeneous environment and moving toward a more favorable environment. We first study the effects of adding a term describing drift or advection toward a favorable environment to diffusion models for …
-
Towards next generation ocean models : novel discontinuous Galerkin schemes for 2D unsteady biogeochemical models
… Discontinuous Galerkin (DG) method for solving advection-diffusion problems is described, including a discussion on schemes for solving higher order derivatives. The discrete formulation for advection-diffusion problems is detailed and implementation issues are discussed. The Hybrid …
-
Massively parallel solver for the high-order Galerkin Least-Squares method
… discretization of the Poisson equation, the advection-diffusion equation, and the Euler equation. The Robin-Robin interface condition is extended to the Euler equation using the entropy-symmetrized variables. The BDDC method maintains scalability for the high-order discretization for the …
-
A finite volume discretization method for flow on structured and unstructured anisotropic meshes
This project is concerned with advection discretization technology within the field of Computational Fluid Dynamics (CFD). To this end, two novel methods are proposed which are dubbed the Enhanced Taylor (ET) Schemes. The model equation for this work is the advection-diffusion equation with the …
-
Numerical modelling of solute transport processes using higher order accurate finite difference schemes. Numerical treatment of flooding and drying in tidal flow simulations and higher order accurate finite difference modelling of the advection diffusion equation for solute transport predictions.
The modelling of the processes of advection and dispersion-diffusion is the most crucial factor in solute transport simulations. It is generally appreciated that the first order upwind difference scheme gives rise to excessive numerical diffusion, whereas the conventional second order central …
-
Solution of the advection equation using finite difference schemes and the method of characteristics
… a prediction is achieved by the solution of the advection-diffusion equation. At present, there exist many numerical techniques which can be used to solve the advection-diffusion equation. The major difficulty when considering undertaking such a simulation, is what method should be used to …
-
Stabilized Explicit Time Integration for Parallel Air Quality Models
… density. Most air quality models are based on advection-diffusion equations. These differential equations are moderately stiff and require appropriate techniques for fast integration over large intervals of time. Implicit time stepping techniques for solving differential equations being …
-
On the Potential Impact of Curved Meshing for Higher-order Adaptive Mesh Simulations
… adaptive finite element methods for the advection-diffusion PDE in both Cartesian and polar coordinate systems, with the polar coordinate transformation serving to demonstrate the potential benefits of incorporating curvature into an adaptive meshing process. Results are presented for …
-
Selenium Distribution and Cycling in the Eastern Equatorial Pacific Ocean
… sediments. However, using a combination of advection/diffusion modeling, particulate Se(0) data, and <sup>234</sup>Th-derived flux rates, the dissimilatory reduction of selenium was shown to mainly occur in situ, rather than via advection/diffusion from coastal sediments.</p>
-
A Web-based finite element model for heat transfer
… is reviewed and the technique applied to the advection-diffusion equation for the transport of temperature. The Java code and graphical interface used to implement the solver for use on the Internet is discussed.
-
Stabilized Finite Element Formulations for Flow Problems
… we begin with a study of the Stokes and advection-diffusion equations. From our study of the Stokes equations we learn that stabilized methods based on enriching the velocity trial function space with bubble functions are only stable for triangular elements. We also present a stabilized …
-
The evolution of ocean fronts in the presence of mixed layer turbulence
… wind balance with time-evolution due to an advection-diffusion balance in the buoyancy equation. In the absence of surface forcing this advection-diffusion equation admits similarity solutions describing a spreading front where the spreading results from shear dispersion associated with the …
-
Multi-dimensional Upwind Fluctuation Splitting Scheme with Mesh Adaption for Hypersonic Viscous Flow
… test cases include advected shear, circular advection, non-linear advection with coalescing shock and expansion fans, and advection-diffusion. For all scalar cases the fluctuation splitting scheme is more accurate, and the primary mechanism for the improved fluctuation splitting performance …
-
Asymptotic Analysis of Perturbations to Travelling Wave Solutions of Nonlinear Advection-Reaction-Diffusion Equations of Fisher Type
In this thesis we examine some nonlinear advection-diffusion-reaction equations of Fisher type. First we discuss the stability properties of the equations by writing each nonlinear equation as a system of two ordinary different equations and then analyzing the stability of their equilibrium …
-
Transport-limited aggregation and dense granular flow
… proposed to generalize Laplacian growth such as diffusion-limited aggregation (DLA) and viscous fingering. The fractal properties, crossover in morphology, and relation between continuous and stochastic growth are studied in the context of a representative case, advection-diffusion-limited …
Page 1 of 5