Meshing problem in a constricted geometry
 

Hi,

I want to simulate the blood flow in a simple model and I have a constricted geometry (as a whole body).

I applied edge sizing to the outer and inner diameters of the geometry by using number of divisions option and hard behaviour. The number of divisions from the beginning of shorter part to the end of longer part is as follows;
for outer diameter -> 20, 30, 150 and 75.
for inner diameter -> 15 and 75

However, I got such a mesh (just the edges are divided but the parts between edges are unstructured and the element sizes are random).

I want to obtain a structured mesh (aligned in the flow direction) with a transition of element sizes (getting smaller) from small number of divisions to large number of divisions through the body.

I tried sweeping method but ansys mesher says that this body is non-sweepable. How can I succeed to obtain such a mesh?

Regards,
Kamil