[aerocfd]

Hello,

So I am trying to simulate a train in a tunnel in a vacuum condition.

First Question, Do I need to always consider compressible flow? or is compressible flow only for velocities of greater than mach 0.3 ?

Second Question, if I want to model it as compressible flow, for the boundary condition if I use pressure-inlet then how do I make my train move in the flow? because by using velocity-inlet which I suppose is for incompressible flow you can give magnitude and direction and keep the train stationary.

Thank you for your time.