Hi @AnnaFless @mehakkar123,
There are two solvers which are commonly used for simulating the compressible flows, including “rhoCentralFoam” and “sonicFoam”. The former is a density-based laminar solver and the latter is a pressure-based solver which can takes the effects of turbulence into account. The sonicFoam needs higher grid resolution to achieve the same accuracy and its pressure-based characteristics necessitates more iterations per time-step for the high-Mach number flows. Concerning the rhoCentralFoam, the quality of the grid has a huge influence on the solution stability.