[davistib]

I'm trying to use the ENGINE_INFLOW_TYPE boundary conditions, without much luck.

The FAN_FACE_MACH and FAN_FACE_MDOT seem to do nothing, as in no BC gets applied (or it defaults to something else under to hood?).

FAN_FACE_PRESSURE seems to work as expected, but I don't know what the difference between that and just MARKER_OUTLET is, the behavior seems identical.

Specifics:
Simulating an inlet in supersonic flow. The freestream Mach is 1.64 and I have the inlet internals initialized as subsonic Mach 0.5 using the SUBSONIC_ENGINE_CYL options.

I'm initially running the inlet outflow (AIP) using the BC MARKER_OUTLET = ( AIP, <pressure> ), which works fine.

Ideally I'd like to specify an average Mach at the AIP, or a constant mass flow, for design simulations. I tried using the MARKER_ENGINE_INFLOW boundary conditions like

ENGINE_INFLOW_TYPE= FAN_FACE_MACH
MARKER_ENGINE_INFLOW = ( AIP, <aip_mach> )

or

ENGINE_INFLOW_TYPE= FAN_FACE_MDOT
MARKER_ENGINE_INFLOW = ( AIP, <aip_mdot> )

but nothing is happening.. it looks like the BC defaults to a characteristic outflow or something and there is no sensitivity to the solution to any value specified for <aip_mach> or <aip_mdot>.

If, however, I use

ENGINE_INFLOW_TYPE= FAN_FACE_PRESSURE
MARKER_ENGINE_INFLOW = ( AIP, <aip_pressure> )

Then the solution matches identically the result of using MARKER_OUTLET = ( AIP, <aip_pressure> )