Pressure Recovery Factor
 

Hi All,

I computed supersonic/subsonic ramjet simulation using openFOAM. I applied supersonic inlet conditions at inlet and constant pressure outlet at exit. There was multiple shocks occurred inside the cowl region. Here i validated the data and found simulation was done properly.

I done the simulation for multiple cases like various mach number and various angle of attack. I calculated the pressure recovery factor near the uniform flow region after the multiple shock and before the exit pressure conditions.

I was wondered by seeing the results. As mach number decreases from 3.0 to 2.1, pressure recovery factor has increasing from -0.33 to 1.12. I used the formula to calculate it

prf = (totalpressureatsomepoint-totalpressureinlet)/totalpressureatsomepoint

But i dont know how i am getting PRF as positive value. Is the any trend of pressure recovery factor various at mach number changes ?

regards

ranjith