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 520 for “"advection"”.
-
Advection at a forest site – an updated approach
… forest was investigated. Horizontal and vertical advection are recognized as important terms of the Net Ecosystem Exchange (NEE) budget in addition to the commonly measured turbulent flux and storage flux. Direct advection measurements are challenging because of the instrumental accuracy required …
-
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 …
-
Assessment of scaling and information requirements of the classical advection dispersion equation and a temporal-nonlocal advection dispersion equation at the MADE site, An
… power-law late-time tails that the classical Advection-Dispersion Equation (ADE) is unable to match. The heavy tailing is due to mass transfer into low velocity zones where dissolved solute becomes relatively immobile for certain periods of time. Transport modeling insufficiencies have led to …
-
Diapycnal advection by double diffusion and turbulence in the ocean
… rates are examined and related to diapycnal advection for both double-diffusive and turbulent regimes. The role of double-diffusive mixing at the site of the North Atlantic Tracer Release Experiment is considered. The strength of salt-finger mixing is analyzed in terms of the stability …
-
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 …
-
Finite difference methods for the advection equation / Peter John Steinle
Bibliography : leaves 211-216
-
Diapycnal advection by double diffusion and turbulence in the ocean
… rates are examined and related to diapycnal advection for both double-diffusive and turbulent regimes. The role of double-diffusive mixing at the site of the North Atlantic Tracer Release Experiment is considered. The strength of salt-finger mixing is analyzed in terms of the stability …
-
Determination of advection and diffusion in a thermohaline staircase region
… of double-diffusive mixing to the regional advection - diffusion balance is the subject of this study. Using hydrographic and current meter data collected in the C-SALT program of 1985 (Schmitt, 1987), we construct inverse models in both cartesian and density coordinates and seek bounds on …
-
STRUCTURE-OPTIMIZED AND ORDER-PRESERVING METHODS FOR ADVECTION AND TIME STEPPING
… with long-time accurate solutions in complex advection-dominated problems, we first address whether there are numerical schemes for constant-coefficient advection problems that can yield convergent solutions for an infinite time horizon. After establishing a new notion of convergence in an …
-
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 …
-
Chaotic advection and mixing in a western boundary current-recirculation system : laboratory experiments
… hyperbolic points gives rise to a chaotic advection mechanism known as 'lobe dynamics'. These lobes carry fluid in and out of the recirculations, acting as extremely effective stirring mechanisms. I demonstrate the existence of these exchange lobes in the unsteady hyperbolic (figure-8) …
-
Chaotic advection, mixing, and property exchange in three-dimensional ocean eddies and gyres
… importance of diffusion as compared to chaotic advection for tracers in this system. Three methods are used to quantify the relative contributions: scaling arguments including a Lagrangian Batchelor scale, statistical analysis of ensembles of trajectories, and Nakamura effective diffusivity from …
-
Theoretical and numerical aspects of advection-pressure splitting for 1D blood flow models
… in the non-conservative one, are split into advection and pressure terms: in this way, two systems of partial differential equations are obtained, the advection system and the pressure system. From the mathematical as well as numerical point of view, a basic problem to be solved is the …
-
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
-
Chaotic advection and mixing in a western boundary current-recirculation system : laboratory experiments
… hyperbolic points gives rise to a chaotic advection mechanism known as 'lobe dynamics'. These lobes carry fluid in and out of the recirculations, acting as extremely effective stirring mechanisms. I demonstrate the existence of these exchange lobes in the unsteady hyperbolic (figure-8) …
-
Chaotic advection, mixing, and property exchange in three-dimensional ocean eddies and gyres
… importance of diffusion as compared to chaotic advection for tracers in this system. Three methods are used to quantify the relative contributions: scaling arguments including a Lagrangian Batchelor scale, statistical analysis of ensembles of trajectories, and Nakamura effective diffusivity from …
-
Similarity Solutions for the Two-Dimensional Diffusion–Advection Equation in Sharp-Corner Geometries
… symmetry method is applied to the 2D diffusion-advection equation to obtain a similarity ansatz, reducing the equation to a time-independent second-order PDE. By modifying the ansatz, the problem can be recast as an eigenvalue problem. Exploiting elliptic regularity and the strong maximum …
-
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 …
-
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 …
-
Solution of advection-dominated transport by Eulerian-Lagrangian methods using the backwards method of characteristics
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1987.
Page 1 of 26