Problem with gaps between interfaces MRF Ansys Teaching Workbench 2025

[annapir]

I want to simulate fluid flow of a ceilling fan in a room. I created two enclosures - one smaller for rotating domain and one bigger for a room. Extracting smaller enclosure from the bigger one caused problems, during the simulation I noticed gaps between rotating domain and room which cause the program to insert wall ( I get zone-surface: cannot create surface from sliding interface zone.Creating empty surface. message in Ansys Fluent. This walls cause problems in air flow as shown in the pictures. I tried also manually cutting rotor from the rotating domain and rotating domain from the room by selecting pull surfaces and  combine instead of doing enclosures. But it doesn't fix the problem. I tried doing geometry in DesignModeller instead but it also doesn't fix the problem. Do you have any ideas on how to fix it?

[Rob]

Can you replot the above with node values off? The fact I can see mesh edges in the smoothed contour suggests it may be a meshing problem: ie you don't have enough cells or there's too big a jump in size over the interior.