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-   -   ask a question about Fixed Flux Boundary Condition (http://www.cfd-online.com/Forums/phoenics/52279-ask-question-about-fixed-flux-boundary-condition.html)

mahe July 14, 2008 22:44

ask a question about Fixed Flux Boundary Condition
 
Hello everyone.

When I read polis about Fixed Flux Boundary Condition,I meet a problem.In the polis,it says that V should be setted to source/C.In the latter example, Heat source in block:-10 MW/m**3,then PATCH(HEATEDBL,VOLUME,NX/4+1,3*NX/4,NY/4+1,3*NY/4,1,1,1,1) COVAL(HEATEDBL,TEM1,FIXFLU,1.0E7) I find V=1.0e7 rather than 1.0e7/fixflu.Does phoenics change it automatically? Another question, does VOlUME mentioned in the PATCH represent the Volume of a cell?

Thank you. waiting for your answers.

Jalil Ouazzani July 15, 2008 04:21

Re: ask a question about Fixed Flux Boundary Condi
 
Hello Mahe, Sources with Fixflu have a special treatment, they are written as:

Sphi = Fixflu * (Val /Fixflu - Phi) in such a way that the final source introdude in the equations is: Sphi = Val - Fixflu * PHI (there is an error of the order of fixflu*phi (fixflu=1.e-10). This done automatically and only for Fixflu. If one wants to do the same thing with a smaller coefficient, he needs to divide the value he wants to impose by the coefficient. Hope this help, Jalil


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