Failed to evaluate variable jacobian!..

Hi everybody,

I want to simulate a heat transfer and navier stokes problem. I have two subdomains. In one of the subdomains only the heat transfer equation is solved, not the navier stokes equation.

To implement this condition I uncheck the tick of the navier stokes application mode "valid in this subdomain"

But I encounter and error error 6250 "Failed to evaluate variable jacobien" variable u subdomain....

I cannot find anything about the error code 6250..

What could be the problem?

How can I solve this problem?

atilla savas