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-   -   Robin boundary condition for the velocity (http://www.cfd-online.com/Forums/openfoam/85832-robin-boundary-condition-velocity.html)

fumiya March 8, 2011 04:46

Robin boundary condition for the velocity
 
Hi all,

I'd like to know how to impose the following boundary condition for the velocity U.

-----velocity boundary condition-----------------------------------
*normal component(Un=U・n): Neumann B.C.
*tangential component(Ut=U-(U・n)n): Robin B.C.(A*dUt/dn + B*Ut = C)
*A,B and C are not constants but variables
-------------------------------------------------------------------

Is it possible using existing utilities?
Do I need to implement new boundary condition?

Thanks,
Fumiya

Bernhard March 8, 2011 06:01

You can give it a try with groovyBC, however, I'm not sure if you can define the tangential component like that, you can check it here:
http://openfoamwiki.net/index.php/Contrib_groovyBC

fumiya March 8, 2011 06:49

Hi Bernhard,

Thank you for your reply.
I tried with groovyBC, however, I think I can't change bc type
with the direction because fractionExpression is a scalar.

Dirichlet (fractionExpression=1)
Neumann (fractionExpression=0)

Martin80 June 10, 2011 06:50

Hi Fumiya,
I am looking for robin bc too. Have you allready found an hint how to implement it in OpenFoam?
B.r.,
Martin.

fumiya June 17, 2011 02:58

Hi Martin,

The solver named "adjointShapeOptimizationFoam" contained in OpenFOAM
V2.0.0 could be of some help.

Hope That Helps,
Fumiya



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