snappyHexMesh and concave cells
 

Hello,

I playing a bit with snappyHexMesh and I got messages from checkMesh concerning concaveCells.

Here is what I found out,

I only create the castellated mesh and checkMesh finds concave cells. So I displayed some of them with paraView. It seems, that the cells between the refinement layers - the cells that actually do the transition in fineness - are the concave ones.

Is it possible, that this cells are considered concave because they are partially refined? I.e. one side of the cells is delimited by one face and the opposite side of the cell is delimited by e.g. four cells?

I will try a little ascii art. v is a vertex. The top is one single face and the bottom consists of two faces. Is the bottom side of the cell considered concave?

v- - - - - v
|
|
|
v- - v- - v

I'm gonna have to bump this, cause I have the same question. Did you find an answer? And do you know how one would go about reducing the number of concave cells in a mesh?

Yes I found the answer and it is also contained in my question.

It is also explained in this post http://www.cfd-online.com/Forums/ope...tml#post452712


In some cases you can't reduce the number of concave cells. If the concave cells solely originate from refinement, then there is nothing you could do about it.

So in cases the reports about concave cells have to be taken with a grain of salt.