[nvtrieu]

Hi every one,

I am doing simulation the turbulent flow over NACA 0012 wing at Re 1.2e5.

I want to check the Cd/Cl at various AoA and then compare with experimental data from NACA foils (theory of wing sections)

I used steady, k-epsilon, standard wall function model. The other parameters are default. The unstructured mesh is used.

The results are not accurate for both Cd/Cl. The maximum error of Cd is 50% (AoA from 0~15deg). For Cl, the maximum error occurs at 30deg (stall), arround 30%.

Now I am trying to refine the mesh by using prism layer around the wing surface. The first grid is set to the value that generates the y+ <1. In order to solve for the boundary layer. And also change the turbulence model to k-omega SST.

The new problem is: after refine the mesh near the wing by using mesh sizing function I check the mesh quality: cell quality, skewness, orthogonal are very good. Then I use the inflation mesh to generate the prism layer for boundary layer. After finish, I check again the mesh quality. Both skewness and orthogonal are good but the cell quality is low. I dont know why??

Could any one tell me what is wrong and how what should I do to get a accurate results?

Thank you very much.