[hammad66]

Help/ Suggestions Required!!

I am performing CFD on 3d wing (transonic region) with winglet attached to it. The solution converges when angle of attack is from 0-3 degrees. But when angle is increased to 4 degrees and above, the solution is not converging. Cd and Cl keeps on fluctuating.

I am using SA model.

[Stanley90]

Originally Posted by hammad66

Help/ Suggestions Required!!

I am performing CFD on 3d wing (transonic region) with winglet attached to it. The solution converges when angle of attack is from 0-3 degrees. But when angle is increased to 4 degrees and above, the solution is not converging. Cd and Cl keeps on fluctuating.

I am using SA model.

Hi. For me it's just too strong flow separation, which is hard to converge using SA turbulence model and I'd suggest switching to k-e. Other questions are:
1. Is you mesh refined enough?
2. What solver do you use and what order advection scheme did you choose? If higher than first-order go back to first-order and then see what happen.
3. Does Cd and Cl convergence is not changing within angle change? It's seems strange..