Set Up Compressible Flow Modeling
Simulate high speed flows with speeds ranging from subsonic to transonic up through low supersonic conditions. Compressible flow simulations should be conducted using a transient analysis with ideal gas properties for air. AcuSolve will compute the coupled system of compressible NS equations with a single nonlinear iteration using the "compressible_flow" stagger. Compressible flow is compatible with the supported turbulence models and most other existing AcuSolve features
 General usage

 Analysis must be transient.
 Heat transfer should be on with or without turbulence active.
 Inflow boundary conditions

 Stagnation pressure inlet and static pressure outflow are the preferred boundary condition specifications.
 Subsonic conditions require two variables as input while supersonic conditions require three.
 Mach number is computed by $Mach=\sqrt{\gamma RT}$ and positivity of both pressure and temperature are checked by AcuPrep.
 When the specified inflow condition is subsonic, pressure is ignored, and only velocity or Mach number and temperature are used as the boundary conditions.
 Outflow boundary conditions

 Subsonic: The userspecified pressure is fixed.
 Supersonic: The userspecified pressure is ignored if it is lower than the computed pressure on the outflow surface.
 Nodal initial conditions

 It is important (critical in most cases) to specify valid initial values for all the solution quantities. Pressure and temperature must be defined such that density is realistic.