MATHEMATICS SEMINAR by Raytcho Lazarov

Koç Üniversitesi

Date : December 13, Friday

Time : 12:30

Place : ENG 16

Refreshments will be served at 12:15

Raytcho Lazarov

Texas A&M University

“Numerical simulation of flows in highly heterogeneous porous media”

Abstract:

We shall present an overview of some approximation strategies and robust solution methods

for the resulting algebraic system for numerical solution of ows in highly heterogeneous

porous media. Our main goal is derivation of numerical methods that work well for both,

Darcy and Brinkman equations, and could be used either as (1) a stand alone numerical

upscaling procedure or (2) robust (with respect to the high contrast of the porous media)

iterative solvers for the finite element approximation on a fine-mesh spatial scale. The pre-

conditioners are based on overlapping domain decomposition technique. The robustness with

respect to the contrast is achieved via special construction of a coarse grid space that in-

cludes patched together eigenfunctions corresponding to the smallest eigenvalues of properly

weighted local spectral problems. This approach has a natural abstract framework which we

shall discuss as well.

The main target of our applications are numerical upscaling and simulation of uid ows

in highly heterogeneous media modeled by Brinkman, Darcy, and steady-state Richards’

equation (with relative permeability governed by Haverkamp or van Genuchten relations).

Joint work with Y. Efendiev, J. Galvis, K. Shi and J. Willems