Whats the problem with k-epsilon model?
 

I have simulated a high performance unmanned air craft and compared the results with windtunnel results. the drag is matching but the lift is not. i have used k-epsilon turbulence modeling. CFD is under predicting the lift. can any one say why?
:confused:

Please provide some additional details regarding your convergence criterion, whether your simulation is converged, what is the wall treatment you are using, also by how much is your Cl amiss from the windtunnel results.

Have you tried using a finer mesh?