[sgbaek]

I would like to consult my issue regarding the hybrid initialization. I am modeling a nozzle compressible flow into a vacuum (or a low pressure chamber) with pressure inlet and outlet boundaries. It is largely based on a youtube tutorial: https://www.youtube.com/watch?v=27zclV3c6oM)

One thing I found with the hybrid initialization is that it assigns finite pressure, velocity, and density inside the simulation domain. The figure attached shows the initial pressure profile after the hybrid initialization. One can see that ANSYS assigned the pressure down the pipe.

However, since I am interested in the propagation of the flow, I do not think this was a correct initialization. I kind of expected to have zero pressure within the simulation domain, and I could see the flow propagation down the pipe to the chamber. I patched the internal region with the zero pressure, but the solution diverged even at the 1st step.

My question is whether this hybrid initialization is a proper way to examine the arrival time of the gas at a some distance away from the inlet boundary? This delayed rise at a given location and the time it takes to reach the steady state are my two goal from this simulation.


Thanks,

John