Pressure field in mixed convection
 

Hi, I have written a code to simulate fluid flow inside a vertical channel using SIMPLE algorithm, everything was ok until I added buoyancy forces ( (rho_infinity - rho) * g * Volume) to y_momentum equation. after doing so the code converges but the pressure field does not seem correct to me since it has lower values in inlet than outlet.

considering I have set velocity inlet boundary condition (v_in = 0.01 m/s) I expect to get higher pressures at inlet than outlet.

after some investigation I found that the reverse pressure gradient is equal to hydrostatic pressure field of the fluid but in reverse direction. :confused::confused::confused:

Any comments are appreciated.