[kael]

Hello guys!

I'm running an external flow 2D airfoil simulation in low Reynolds Number ( 50,000-100,000) for multiple AoA. The simulation data then compared with the experiment for validation of the model.

The detail for my simulation model:

1. Incompressible
2. Pressure-Based and Steady-State Solver
3. Transition SST model (4 eq.)
4. Inlet : Velocity Inlet
   Outlet : Pressure Outlet
   Airfoil : Wall with no-slip condition.
5. ICEM Meshing, with y+ 0.1
6. Turbulence Intensity and Viscosity Ratio are 0.06% and 10, respectively (based on the experimental condition).

The objectives are to get the aerodynamics coefficient close to the experiment and examination of separation bubble on multiple AoA. Result shown for Cl are close to the experiment, but my Cd are unsatisfactory. More over, my Cp distribution at x/c where the bubble exist are way-off (Image on attachment, Cp distribution of Eppler 387 at 0 degree for Re 100,000)

I'm aware that Fluent gives us control to the transition correlation in the UDF for the model. I'm planning to use the calibration for Flength and Reθc (e.g. P.Malan, Calibrating the γ-Reθ Transition Model for Commercial CFD). Unfortunately, i'm quite new to the UDF.

So, if anyone here have experience using this transition correlation UDF and can guide me through it? (i have read the UDF's manual but the example are using constant only).

Best regards