Dear Federico,

The boundary conditions I mentioned before, in my first post, are actually those listed in the paper. Unfortunately, this is not working since I ended up with the contours' plot I attached, without any shockwave pattern captured.

For this latter case, I also monitored the mass imbalance (difference between the mass inflow and outflow) and this turned to settle around 160 [kg/s], that makes no sense since it should be around zero.

After that, I tried to replicate the very same procedure described in the video you suggested.

In this case I got the following contours:

Still, these results are not that good, besides the fact that the mass imbalance in this case settled around -150 [kg/s]. Just to let you know, I also introduced an automatic mesh adaption, as suggested in the video you shared.

Moreover, in both of these simulations I got the message about the "reversed flow", that make me think about a possible error in the mesh grid.

I hope to hearing from you soon,

Thank you