potentialFoam sensitivity to high aspect ratio cells
 

Dear all,

Currently, I am simulating a 3d object in free-stream air flow. Eventually, I want to use a turbulence model and study the boundary layer (separation) on this object. Since I am taking a step-by-step approach I first want the potentialFoam to work.

The mesh is a structured, conformal, hexahedral block-mesh made in Salome.

My problem:
Simulating with a relatively coarse mesh does not pose any problems. In checkMesh, no errors are given and also the solution converges well to the expected solution velocity field. However, if I now go towards a more fine boundary layer mesh that I also want to implement in the turbulent simulation (with y+~1), the checkMesh poses an error that the aspect ratio is too high (i.e. max 3000). Using foamtovtk, I saw these high aspect ratio cells are at the boundary layer. Now, the potentialFoam solution diverges.

My question:
1. Why would the potentialFoam solution diverge with this? The solution does not depend on the boundary layer since this is not taken into account in potentialFoam.
2. Is the turbulent simulation (simplefoam) less sensitive to these high aspect ratio cells? I saw many simulations that did not have any problems with high aspect ratio cells.

Thanks in advance!