SimScale CAE Forum

Fluid interface error


I’m running some CFD tests (here a PCB heat sink cooling in CHT, basically a remake of the “Heat sink-Electronics cooling using CHT” tutorial).
I’m hitting the wall while trying to set an interface between solid and fluid with face sets, with the following message:
“Error: Fluid interface should have exactly one unique pair of master and slave entities.”
I’ve checked that the sets weren’t used elsewhere, tried to swap sets, change for single faces, … without success.
I guess that the reason is trivial, but can’t point it out!

Any hint would be welcome!

Hi @pdesmarez,

Sorry for the late response! Tagging our CHT expert @sjesu_rajendra here. I am sure he can help you out with your problem.



Thanks for tagging me in @jousefm!

Hello @pdesmarez,

“Error: Fluid interface should have exactly one unique pair of master and slave entities.”

^^This error occurs because the CHT solver requires individual faces to be mapped onto corresponding faces of adjacent solids. Hence the interface definition should have a single face as Master and its counterpart in the adjacent solid as Slave (topo sets might not work). This might be too much overhead to define all the interfaces.

In this regard kindly note that the interfaces are automatically defined when the mesh is generated and hence interface assignment is not required at all. This can be seen from the mesh log.

Please try to define all the boundary conditions, leaving alone the interface definitions and proceed with the simulation run.

I hope this clarifies!



Thank you very much!
It’s so convenient that it may be a good idea to mention it in the tutorials too! (I guess I’m not the only newbie around…)

Best regards,

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Pierre (@pdesmarez),

Thank you for the feedback!! I’ve forwarded this info to the concern person.