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-   -   Transient - Momentum Source (http://www.cfd-online.com/Forums/cfx/21216-transient-momentum-source.html)

stex_ May 2, 2005 11:31

Transient - Momentum Source
 
In this days I run some stationary problems in a module of heat exchanger at low Re appling a "Momentum Source" and "periodic" boundary condition for inlet-outlet.

Growing up the velocity we know that in this problems we have some non-stationary effect, so the question is: "Is it possible to define a momentum source in a "transient" simulation?"

In theory if you define a Mom.Source you specify a constant deltaP, but in a transient phenomena the delta P is variable!

In fact I tried and after some iterations the solver stopped due to very high Mach number (floatin point error)!!!

Maybe someome can help me to turn the problem...

THANKS.

Glenn Horrocks May 2, 2005 18:44

Re: Transient - Momentum Source
 
Hi,

Yes, it is possible to implement a transient source. I suspect your floating point error is caused by divergence in the simulation.

Regards, Glenn

stex_ May 4, 2005 09:10

Re: Transient - Momentum Source
 
Ok, but I've tryed with both constant and time-dependent values of the Mom. Source (e.g. t*100) and everytime I got the same error. The mesh is ok, because with stationary run, I got good results.

How do I have to proceed?

Thanks


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