Operations Research Seminar
Hamiltonian Systems and Liouville Equations with Discontinous Hamiltonians:
Computation of High Frequency Waves in Heterogeneous Media
|
Shi Jin, Professor
Department of Mathematics
University of Wisconsin
|
Wednesday
November 11th
12:00- 1:00 pm
|
Math 1-122A |
We introduce Eulerian methods that are efficient in computing high
frequency waves through heterogeneous media. The method is based
on the classical Liouville equation in phase space, with discontinous
Hamiltonians (or singular coefficients) due to the barriers or
material interfaces. We provide physically relavant interface
conditions consistent with the correct transmissions and
reflections, and then build the interface conditions into the numerical
fluxes. This method allows the resolution of high frequency waves without
numerically resolving the small wave lengths, and capture the correct
transmissions and reflections at the interface. Moreover, we extend the
method to include diffraction, and quantum barriers. Applications to
semiclassical limit of linear Schrodinger equation, geometrical optics,
elastic waves, and semiconductor device modeling, will be discussed. |