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-   -   Help please:Inlet Boundary Conditions!!! (http://www.cfd-online.com/Forums/cfx/19266-help-please-inlet-boundary-conditions.html)

David October 30, 2002 22:22

Help please:Inlet Boundary Conditions!!!
 
Hi CFX users,

I want to specify pressure and mass flow rate at the same time on inlet of a pipe. Is it possible? For example, 15atm and 1.6e-004kg s^-1. Thanks in advance.

David

Fabian October 31, 2002 03:51

Re: Help please:Inlet Boundary Conditions!!!
 
Are you simulating compressible or incompressible flow? In incompressible the absolute value of pressure is of no relevance as only pressure-gradients appear in the equations.

David October 31, 2002 09:56

Re: Help please:Inlet Boundary Conditions!!!
 
Thanks, Fabian. I am simulating two-phase flow, one phase is gas and the other is liquid.

Robin October 31, 2002 11:30

Re: Help please:Inlet Boundary Conditions!!!
 
Hi David,

It is not possible to define both pressure AND mass flow at an inlet (unless it is a supersonic inlet, it which case it is necessary), nor does it make sense to do so. You will need to specify a pressure boundary condition elsewhere in your simulation (either another inlet, an outlet, or an opening). The pressure field will then be determined based on momentum and continuity.

Regards, Robin

David October 31, 2002 20:03

Re: Help please:Inlet Boundary Conditions!!!
 
Hello Robin

Thank you very much for your answer. Now I understand it.

Many regards David


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