How to initialize compressible flow analysis in Ansys Fluent?
Initialization of steady-state compressible flow analysis can be done in best way by using FMG initialization. The initial values set by the FMG initialization are very close to the steady calculation result, thereby it improves the convergence and the stability of the actual computation. FMG initialization, internally solves for Euler equations (non-viscous) and that solution is used as the initial solution for actual compressible flow analysis. When FMG initialization does not give physical initial solution, some of the parameters of the FMG initialization can be changed.
For more details, please refer to the document given below: