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-   -   BuoyantPressure & non-vertical interface (http://www.cfd-online.com/Forums/openfoam/70740-buoyantpressure-non-vertical-interface.html)

Schag December 4, 2009 04:41

BuoyantPressure & non-vertical interface
 
Hi all,
I get a problem with non-vertical interface and buoyantPressure.
When I make a test case with this combination and a closed volume, where there should theorically be no movement, the result is a flow going up along the non-vertical interface. I think this comes from my pressure field but I have no idea concerning the solution.
I cannot use zeroGradient for pressure because I use interFoam, so there would be non conservation of VOF.

Has anyone already faced this problem? Any idea about the solution?
Help me please...

Schag December 7, 2009 05:19

No one faced the same problem????
Please, I'm looking for a solution for 2 weeks now, I'm running out of ideas...

Schag December 7, 2009 12:23

1 Attachment(s)
a view of my problem:

no inlet, no outlet.
boundary condition on the cone
p: buoyantPressure
U: slip
alpha: zeroGradient

if it helps...

jploz December 11, 2009 05:25

Hi Julien,

I can only guess. Did you try a no-slip wall at the cone? I've observed something similar with interFoam-1.5, so I don't think it is related to the pressure BC: Water in a box without inlet/outlet was moving and didn't stop.
I think this is caused by the choice of the solver. The interFoam solver is (imo) not suitable for such type of simulations. More appropriate would be settlingFoam or something similar.

Disclaimer: This is just a guess and I did not investigated this further.

Just my 2 cents.
Jean-Peer

lfbarcelo March 12, 2010 17:00

Possible Solution
 
I believe your problem might have to do with you courant number. Try a smaller timeStep, I had the same problem, the courant number may seem fine for the first 10 or 20 steps but then it increases rapidly, because of strange velocities that appear next to the walls.
A smaller time step solved it for me.


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