[muhammss]

Hey.

I plan to do a complete 3D simulation of NREL 5MW wind turbine. For that i am using propeller case in open Foam as the base line case. I generated the complete 3D.stl file for the turbine rotor and use the concept of AMI patches to simulate the turbine. However, the mesh on the surface of blade is not good. Even though i am using the utility surface feature extract, the SMH keep on deleting some parts on the surface of turbine blade.
Does anybody have any idea why it is happening like this? Please let me know what parameters i need to play with to get rid of this problem.
Also i think when i run SMH in parallel the mesh is more weird than in a serial configuration.
I have attached the pictures to get a better idea of what snappyHexmesh is doing.

[c_dowd]

That's almost certainly a refinement issue. Either decrease the cell size of your background mesh or increase the maximum surface refinement in snappy hex mesh, specifically this line:

    refinementSurfaces
    {
        wing
        {
            // Surface-wise min and max refinement level
            level (2 5); // increase the second number
        }
    }

The problem is the original blockMesh doesn't result in enough cells to accurately model those trailing and thin edges after it's been refined, so using smaller cells or more refinement should improve that.