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sa January 11, 2009 03:37

CFX for low subsonic regime
Is CFX good for low subsonic regime or more precisely for mix of low subsonic, transonic and supersonic flow regimes. because i am getting the difficultly in simulating the large plenum volume (where flow is nearly static) and to outlet where flow is at mach no of 0.4-0.9.

Any suggetions will be highly appreciated.

Regards SA

johnny January 11, 2009 15:40

Re: CFX for low subsonic regime
CFX can solve subsonic, transonic, or supersonic flows. I think your issue is that you have such a wide range of timescales in this problem - it would make sense that you are having difficulties in getting convergence in CFX. You will probably need to play around with some settings in order to get a converged solution.

You may need to start the run with a local timescale factor, then switch it over to a physical timescale.

If you have transonic/supersonic flow, it might make sense to run the case with boundary conditions such that the flow is subsonic. Then once that case is converged, gradually increase the bc's to get the desired operating conditions.

sa January 12, 2009 08:36

Re: CFX for low subsonic regime
Thanks johnny for your quick response.

what is local time scale factor and how it affects the solution.

actually i am simulating the super sonic wind tunnel with inlet large tank (where flow is almost stationary) but in test section flow is super sonic. any suggestions?

best regards

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