[ari003]

Hello everyone,
Hope you all are doing good. I'm stuck with an issue with gmsh which might be pretty simple for few.
The problem statement is as follows:-
1. I'm trying to do a numerical analysis in SU2 before creating the mesh in GMSH platform.

2. The scenario is a simple DFVLR airfoil simulation in transonic regime. My aim is to proceed with unstructured meshing concept.

3. The picture (pic 1) is attached below which represents the automatic meshing.

4. But I need to refine the region adjacent to the airfoil wall. So, I used 'Transfinite curve' option in GMSH (picture 2.)

5. By doing so when I export it in .su2 format and run it in SU2 it gives an error - Zero CV area found.

6. When I remove the 'Transfinite curve" option and proceed with normal automatic meshing it runs completely fine but the y+ is in the buffer region (which is undesirable for my case).

7. After encountering these error I tried to do some hit and trial case and noticed these as follows:-
a. When the transfinite curve option is set until 25 it runs fine until
convergence but in the demand of more refinement with 26, 30, 40,50
it is giving the same error.
b. Now, I tried to locally use the 'transfinite curve' option with 7 lines and
it gave satisfactory result (picture 3). But when it exceeds to more lines
on the wall the error of divergence was observed in SU2.

My aim is to refine the region around the airfoil but it seems like I'm running out of ideas. If anyone is aware of any kind of solution it will be very helpful. Please let me know if anyone needs more information on the problem.