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Tuesday, September 18, 2007
1:30 PM - 3:00 PM
CNLS Conference Room (TA-3, Bldg 1690)

Seminar

Transition Regime Models for Radiation Transport

Dave Levermore
University of Maryland

Transition regimes are the most difficult to simulate because interactions are plentiful enough to make the kinetic equation stiff and expensive to solve, but not plentiful enough to drive the kinetic densities to local equilibria. Transition regime models are developed within a framework that includes (1) stationary balance temporal approximations, (2) small-gradient expansions, (3) boundary conditions. This approach is illustrated in the context of monoenergetic photon transport. We will develop new boundary conditions for P-N and show why N must be odd to get a good model. We will also develop some nonstandard closures for P-1.

Host: Bob Ecke T-CNLS