you can used orthogonal grid generation

Trimmed worked pretty well Laith M. Jasim , but I'll give a try to structured mesh, not sure if these refinements can be done so easily tho

You can use (boundary layer mesh which is available in ICM CFD) specially for the regions that have dramatic changes

Increse the number of mesh in the important area

Increasing Mesh Fineness at Critical Areas

You should increase the number of mech.

Use the correct element type and mesh generation

Try with hexahedral elements instead. I normally get pretty good meshes.

agree very much with Blanca Pena's answer

Try to change your method ," Finite element approach" is the better