Hello everyone,

Im running what I think it a relatively simple simulation, but cannot get the solution to converge.

Its an inlet system for a car. A volume for the atmosphere leading to a bellmouth, through a restrictor, to a plenum and then 4 runners.

I ran the sim initially with 5 pressure boundaries on the volume, and a slip wall on the wall that the bellmouth was attached to. I had a pressure boundary at the base of one of the runners.

This ran ok, but then I realised it was in the wrong units. I changed to inches, put a pressure boundary instead of the slip wall and now the model will not converge. I changed a lot, but no matter what boundaries I have on it now it seems to diverge, residuals - DISS goes to Inf and ENTH goes to NaN.

Any suggestions?

Sorry, DISS goes to NaN, ENTH goes to NaN and T EN goes to Inf, although sometimes the divergence is a combination of one or two of these, not necessarily all 3.