CFD Online Discussion Forums - Periodic Boundary Condition on Impeller Section

Hi,

I have a impeller section ( as in the attached image ) and would like to use the Periodic BC on the shown faces ( Pb with Pa and Pb,rot with Pa,rot ).
NOTE: that Pb,rot is on the other side and cant be seen in the image.
I define them as interfaces and tick the periodic Boundary condition option with the automatic compute Offset on.
I am using the MRF method with the top part being stationary.
When i run the simulation, FLUENT shows the following error,

Error: Non-conformal periodic interface with empty intersection.
Primitive Error at Node 0: Couldn't intersect threads 11 and 12.

Primitive Error at Node 1: Couldn't intersect threads 11 and 12.

Primitive Error at Node 2: Couldn't intersect threads 11 and 12.

Primitive Error at Node 3: Couldn't intersect threads 11 and 12.

This is likely due to incorrect specification of periodic
offset values. Please check the offset values specified
and recreate the interface.

Error: Couldn't intersect threads 11 and 12.

Error Object: #f

Because of the blade curvature I dont know how to manually calculate the offset angle.

Please help.

Thanks a lot !!