Dynamic Mesh Help/Advice Needed.
 

Hello,

I am studying VIV on a cylinder with 2DOF. I created this new mesh to satisfy Y+~1 at the cylinder wall. As seen from the image the mesh is a hybrid mesh. The quad section of the mesh is hooked with the motion of the cylinder and they move together.

However after the cylinder displaces ~0.6m to the right the mesh fails due to a negative cell volume.

Dynamic Mesh Parameters-
Smoothing -
SCF = 0.5
BNR = 1
CT = 0.001
NOI = 20

Remeshing -
I set the max and min length scales according to the mesh scale info.
And the max cell skewness was set to 0.6.

Can anyone advise me on how to stop this negative cell volume?

Thanks

I have been running this case with a time step size of 0.001 s, and 20 iterations per time step.
Any help would be greatly appreciated.

Attached are two images of the failed mesh.

Thanks

New Mesh Failing
 

Guys,

Here is another mesh I made, and it to is failing. Am I missing something obvious whilst making these meshes? Any suggestions on how to improve this would be fantastic.

P