Mach 1 before throat
 

Hello,

I am simulating a jet from a convergent divergent nozzle impinging on a plate to see the pressure build-up on that plate (unsteady simulation).

I apply a "mass flow inlet" boundary condition for my inlet and see that in the first time steps (when the flow is still in the converging part of the nozzle), I have points where Mach > 1... (fully converged within the time step)
I suspect it is linked to the "unsymmetrical" nature of the polyhedral mesh I'm using (worsening away from the inlet boundary).. although it seems fine to me at the inlet (I attach some pictures of the inlet)

Cheers,
Max