Sound wave with external forcing

Dear all,

Recently I derived the MRT force implementation and wanted to test it on some known problems. I decided to simulate a sound-wave propagation with external forcing. I derived some equations and tried to implement them on computer. Few things appeared:

  1. When the bulk and kinematic viscosities are small, the sound wave propagation works fine - the amplitudes of pressure wave and velocity coincide with the derived one. In this case I initialize density and velocity with the equilibrium values.

  2. When the viscosity terms are big, strange things happen. The wave is propagating in a strange way and the amplitude behaves in the awkward way also. I guess it’s the issue of initialization.

If you want to help with it, I can provide with the small document with derived equations and the code.

Thank you,