Sound Speed Extimation
 

Hi Everybody,

I'm simulating train entrance in a tunnel using Sliding Meshes.

I'm solving EULER EQUATIONS with both SECOND ORDER discretization scheme in time and flow equations; Pressure Far Field Boundary Conditions.

I'm using COUPLED IMPLICIT SOLVER on a structured Mesh.

The Time step to Cell Dimension Ratio has been choosen so that:

Dx/Dt > c (Sound Speed)

Yet, when I post process my simulation I find that pressure waves Travel in the tunnel at 318 m/s.....

What do you think about it ??

Thanks in advance,

Jkl.