The free stream condition behaves as both inlet and outlet, and it uses Riemann invariants to determine the flow variables at the boundary. You must specify the free stream Mach number and the static conditions. The supersonic gauge pressure will be used only if the flow enters the domain at supersonic speed. Compressible effects must be enabled before you can specify a free stream condition. Free stream conditions are compatible with the ideal gas equation of state only. When you define a free stream condition, you must position the boundary far enough away from the body of interest to ensure that the flow recovers its far-field state. | |||||||||