Wave Amplitudes for Non-Reflective Boundaries

Richard Wagner

Hello All:

I'm currently implementing a set of non-reflective boundary conditions following the work of Kevin Thompson ("Time Dependent Boundary Conditions for Hyperbolic Systems")and Poinsot and Lele ("Boundary Conditions for Direct Simulations of Compressible Viscous Flows"). I need to derive the Characteristic Wave Amplitudes, called (cursive) L in both papers, for the generic equation that I'm currently working with. (It's different than the standard generic equation.) The problem is, I can't seem to determine exactly how Thompson derives them. He seems to pull them out of the air. Poinsot and Lele also neglect their derivation in their paper. Have any of you generated these yourself? Can you explain the process you used?

This is absolutely critical work for me at the moment, so I'll appreciate any help you can give me.

Thanks,

Rich