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interFoam high velocities near the interface

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Old   April 8, 2016, 16:11
Default interFoam high velocities near the interface
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Arsalan
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Hi Foamers,

I'm using interFoam for simulation of a single bubble motion in liquid container with an extra body force, my boundary conditions are zeroGradient for alpha, fixedFluxPressure for p-rgh and no slip conditon for velocity.
At the moment, I'm struggling with non-physical high velocities near the gas-liquid interface which could cause wrong results and high displacement of the bubble. With a finer mesh, the velocity and displacement decrease slightly but high velocities still here!
The maxCo number is set to 0.1 and the maxAlphaCo number is set to 0.3.

any suggestion and help will be appreciated.

What is the effect of cAlpha that is set to 1.5 (by default) in fvsolution file?!

Thanks in advance,
Arsalan.
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Old   April 10, 2016, 16:19
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Hi Arsalan,

in VOF method that is defined in interFoam we have a extra term that

represent interface compression as below:

cAlpha*Ur*alpha*(1-alpha)

that this term only define in interface.out of interface this term always is zero.

and this term determine compaction of interface.

in small cAlpha diffusion of interface is high and in large one,results are

unphysical.
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Old   April 16, 2016, 22:08
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Hi Arsalan, depending on the case these velocities can be a result of the poor management of curvature in FOAM or other numerical settings. Please post your whole case to check.

Regards!
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