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-   -   Mistake in PISO loop for interFoam solver (http://www.cfd-online.com/Forums/openfoam-solving/60136-mistake-piso-loop-interfoam-solver.html)

kumar2 June 27, 2006 21:04

Hello Friends I was wonderi
 
Hello Friends

I was wondering if there is a mistake in the PISO loop for the interFoam , rasInterFoam solvers.

In Dr. Rusche's PHD page 148,

(Del.V) = 0 , but at the interface density is rapidly changing so shouln't (Del.(rho*V)= 0);

Looking at the PISO loop in rasInterFoam we have laplacian(rUAf,pd)==div(phi) .

should this be changed to something like

laplacian(rUAF*rho,pd) == div(phi*rho)

Thanks a lot in advance

Kumar

kumar2 June 28, 2006 12:57

Dear Friends Could someone
 
Dear Friends

Could someone comment on this post ?

thanks

kumar

eugene June 28, 2006 13:09

No, because the interFoam solv
 
No, because the interFoam solver conserves volume not mass (both fluid are assumed incompressible). This is done specifically to get around the problem of large gradients at the interface.

kumar2 June 30, 2006 18:26

Hi Eugene Thanks a lot for
 
Hi Eugene

Thanks a lot for your reply. I have just one more question.

In equation of 4.28 of henrik rusche's phd thesis we have phi=phi* - (1/A_D)_face * |S|*faceGradient(P)

But in 4.30 we have something like

div( (1/A_D)_face , gradient(P) ] = diver.(phi*)

How is |S|*faceGradient(P) converted to gradient(P) ??

In all openfoam solvers the equation 4.30 is implemented and they are dimensionally correct.

Another question if rUA = 1.0/UEqn.A()

is rUAf = rUA interpolated on the face and multiplied with surface area or it is just rUA interpolated to the faces

Thanks a lot once again

Kumar


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