suction simulation on an airfoil using fluent
For my final year project, I am implementing suction on the NACA 23012 airfoil to improve aerodynamic performance, however, after specifying a suction inlet as a velocity BC and inputting the necessary data, my lift values are too high and oscillating. (for 0 AoA, Cl=4)
The velocity at the suction slot is half that of the velocity at the inlet of the flow domain. the turbulent intensity is 0.01%
the Reynolds number is 6,000,000 and the flow is subsonic incompressible.
How best do I implement suction in the simulation and specify it's corresponding boundary conditions?
Is the suction a pressure inlet or outlet?
Also, since the pressure at the suction slot is less than the atmospheric pressure, do I put a negative sign when inputting the gauge pressure?