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OpenFoam underestimates lift coefficient compared to fluent or XFOIL

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Old   November 21, 2018, 13:33
Default OpenFoam underestimates lift coefficient compared to fluent or XFOIL
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Sergio
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Hello!

I am trying to simulate the flow over an airfoil (NACA23018) using OpenFoam. I am using simpleFoam with the kOmegaSST turb. model. For a RE of about 9.4e06 (200km/hr speed and 1m cord) and an angle of attack of 4, XFOIL predicts Cl = 0.57 and Cd = 0.007. With my current case setup (https://www.dropbox.com/s/8epacpc9be1a0a3/case.zip?dl=0) I am getting a similar drag ( 0.008) but my lift is waay smaller (openFoam Cl = 0.34). The meshing was done in ANSYS and Fluent produces results closer to XFOIL (Cl = 0.56 and Cd = 0.085). I tried to match the settings (BC's, solvers, etc.) as best as I could.
I tried a range of boundary conditions for k and omega. I also tried different sweeping options in fvsolution, increasing nnonorthoganalcorrectors and smaller relaxation factors, but non of those produced the correct solution.
Also, in fvschemes I wanted to experiement with different schemes but switching k and omega in divschemes to second order causes divergence.

My question is this, which prameters would you look at more closely to improve the results and to what would you try to change them to?

Thank very much in advance!

edit: forgot to mention, I tried several meshes and this one gives a y+ of 1
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airfoil, komega sst model, lift, openfoam, simplefoam

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