Problem with boundary layers for cylinder in channel
 

Hi,

I am trying to mesh a quite simple geometry: circular cylinder in a channel (3-D) with cylinder axis along spanwise direction. To do so i triangulate the side wall (wall perpendicular to cylinder axis) of my geometry and extrude the triangles (along spanwise direction) to produce prisms (wedges).

I would like to have boundary layers (with quadrilaterals) at the bottom and upper edge of the face, as well as around the cylinder, and triangles at the rest of the domain. To do so I use “Patch Dependent” as a mesh method. I use ICEM CFD 12.0.1

My main problem has to do with handling the triangles close to the boundary layers, when generating the mesh at the face. At the area around the cylinder where the boundary layer ends, and the triangles start the tris are not spread evenly. I have regions with smaller tris and more dense, and other with bigger tris and less dense. I was expecting the triangles to be spread evenly and symmetric around the cylinder since my geometry is kind of symmetric. This was the case when I was using GAMBIT. I tried to control the height ratio for the triangles on the surface i am meshing from the "Mesh>Surface Mesh Setup" but nothing changed.

I attached images of the mesh using ICEM CFD and also what i was getting when i was using GAMBIT.

Thanks
Nicolas