I have a simulation around the airfoil the field files generated as .f00000 and a binder file .nek5000. I am trying to see if it is possible to extract surface of the airfoil as shown in the video below or calculate the following:
Wall shear stress and the profile from the wall if possible
In the video you reference, the speaker extracts a block of the surface to compute the shear-wall stress on. Your data only has one block, so that won’t work. I don’t know if you can direct Nek5000 to write out this block, but you should be able to extract it in ParaView without too much trouble.
While looking at your data, I noticed that your mesh is not well connected. That is, when you have two hexahedra sharing a face, they are not sharing the same points. That is going to mess up ParaView’s neighbor calculations. You can fix this by running the Clean to Grid filter.
You can get the polygons around that hole in your data by applying the Extract Surface filter (after Clean to Grid). After you apply that filter, things will look the same because you are also extracting the outer boundary of the mesh. You can remove the outer boundary that you don’t want by applying the Extract Cells By Region filter.
In the Cells By Region filter, change the Intersect With parameter to Box. Then, adjust the planes of the box to be inside the boundary. Check the box that says Extract intersected.
That said, it might be better to have Nek5000 compute the wall shear stress if you can. Several people reported problems with computing it post processing including inaccurate velocities on the surface due to boundary conditions.
