[tr.goktug.yilmaz]

Hello all,

I am conducting an analysis in Fluent software, focusing on lift and drag coefficient at different angle of attacks. However, I have noticed that the residual values display fluctuating characteristics and the lift and drag coefficients do not converge to a certain value at 6 and 10 degrees. For 4 degrees, solution converges and residuals do not fluctuate, since flow does not separate. I have attached an image showing the velocity vectors at 4, 6, and 10 degrees and residuals at 6 degrees for reference.

To obtain a more accurate analysis, I am seeking guidance on how to approach this issue. I have tried reducing the velocity at 6 degrees to decrease the flow separation and subsequently decrease the residual values, resulting in a slight convergence of the lift and drag coefficients. However, my analysis involves a Mach number around 0.8, and I am currently using the kw-SST method. I would like to have a converged solution even if there is a flow separation.

I would greatly appreciate any suggestions or solutions that you may have regarding this problem. Thank you in advance for your assistance.

Best regards

[MVLM]

I'm not expert... but did yoy control the Y+? is very important with k-w.

[Yajie_Qin]

Maybe you can try a transient simulation to study the separation manner.