[Colloquium] Talk by Tatyana Vdovina on Wed. October 4, 2006
Margery Ishmael
marge at cs.uchicago.edu
Thu Sep 14 09:12:56 CDT 2006
DEPARTMENT OF COMPUTER SCIENCE - TALK
Date: Wednesday, October 4, 2006
Time: 2:30 p.m.
Place: Ryerson 251
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Speaker: TATYANA VDOVINA
From: University of Maryland, Baltimore County
Department of Mathematics and Statistics
Title: Operator Upscaling for the Wave Equation
Abstract:
Wave propagation in heterogeneous media results in models involving
multiple scales.
Operator upscaling solves the problem on a coarse grid, but still
retains subgrid
information and fine-scale input data. The method applied to the
constant density,
variable sound velocity acoustic wave equation consists of two
stages. First,
the problem is solved for the subgrid component defined locally
within each coarse
block. Then, the subgrid solutions are used to augment the coarse-
grid problem.
Due to the homogeneous Neumann boundary conditions imposed on each
coarse block,
the subgrid problems decouple, which leads to the efficient parallel
algorithm.
Two variable velocity numerical experiments illustrate that operator
upscaling
captures the essential fine-scale information. We develop convergence
analysis for
the method using energy techniques. We show that in the H^1 norm the
upscaled
solution converges linearly on the coarse scale, and pressure (which
is not upscaled
in this implementation) converges linearly on the fine scale if
Raviart-Thomas zero
spaces are used on both scales. The fully discrete scheme is also
shown to be
second-order in time. We also discuss the application of operator
upscaling
to the three-dimensional elastic wave equation.
***The talk will be followed by refreshments in Ryerson 255***
-------------------------------------------------------
Host: Todd Dupont
People in need of assistance should call 773-834-8977 in advance.
For information on future CS talks: http://www.cs.uchicago.edu/events
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