Trouble importing intricate block-structured mesh from ICEM to Fluent
 

Hello everyone,

(This is a thread I had also started in Fluent forum. However, now I think this might be the right place.)

I am having trouble trying to import an intricate block-structured mesh from ICEM CFD. It seems perfectly fine with the quality checks in ICEM but when I try to open the mesh in FLUENT I get a bunch of error messages which are

Error: Build Grid: Aborted due to critical error.

Error: Build Grid: Aborted due to critical error.
Error Object: #f

Error: inquire-nosolve-cell-threads: invalid grid

Error: inquire-nosolve-cell-threads: invalid grid
Error Object: #f

To simply put how my blocks are placed: Imagine a connected series of blocks formed by extrusion in line forming a cycle with vertices merged at the end. The space in the center is also blocked using quarter o-grid (or Y-grid) owing to the geometry. Is importing a mesh of this kind always a problem for FLUENT? How do you think I should handle at least the diagnosis of the problem?
Please do not hesitate to share any kind of experience or opinion with me on this. This is an emergency for me.

Thank you