CFD Online Discussion Forums - [ICEM] ICEM CFD Meshing for a 3D Ahmed body

I am simulating the flow around a 3D Ahmed body (Fig.1) using OpenFOAM and I want to make the computational grid by ICEM in ANSYS.
At first, I created the hex-mesh grid by o-grid, but some grids near the front of the body have a large skewness (Fig.2) and the grids of the surface weren’t vertical to the body (Fig.3).
So, I tried to make the grid by multi-block (Fig.4). I separate the computational domain to two regions. “Region A” is near the front of the body and “Region B” is the other area. In “Region A”, the interface surface grid (shell mesh) was made by hex-mesh only, so to merge to “Region B”. Volume meshes were made by tetra-mesh (Fig.5). I choose Tetra/Mixed for mesh type and Quick (Delaunay) for mesh method. However, this method don't make meshes in shear-layer (Fig.5) and the skewness of the mesh was too high for using it in OpenFOAM.
I can make the mesh in shear-layer well by using tetra-mesh (interface surface is triangle).
So, please teach me some solutions of these.
l How to improve the mesh in shear-layer and skewness of tetra-mesh
l Other solutions of making the grid using hex-mesh.
l How to merge the triangle mesh surface to the quadrilateral mesh surface
I hope someone apply.

Shun HOMMA