I tried the simulation with both SST k-w and Spalart Allmaras for 0 angle of attack. Ideally the lift should be as close to 0 as possible. The result from the Spalart Allmaras is more close to zero than that of SST k-w. Hence the confusion in selecting the model
As the angle of attack changes, the frontal area would also change. So won't we get a wrong drag coefficient if we keep the reference area same?