Mesh a circle with quad element
 

Hi all,
I' trying to mesh a quarter of circle with quad 2D element using ICEM. It works quite fine but in the area where the two edges of the quad block, that I have associate to the curve, converge the quality of mesh is every time lower than in others regions.
Here the elements are too much deformates.

I tried to do an o-grid inside, but id doesn't work.
Can someone link me some useful tutorials on how to do? (it's a problem I never learn how to fix :mad:)

I add some imagines.