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Multiphase VOF Taylor bubbles

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Old   September 10, 2021, 09:18
Default Multiphase VOF Taylor bubbles
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Dominik Regner
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I am trying to simulate sigle Taylor bubble in the microchannel (0.8mm height) Its 2D simulation of half of the channel.

Everything seems to work normal with sufficient results with lower mesh size.
With settings:
VOF
Explicit
P-V:PISO
LeastSquares Cell Based
PRESTO
Second order upwind
Georeconstruct.

But with finer mesh (Same shape of cells) the solution starts to blow up. Bubble is collapsing.

Is enyone able to help me? I need to have finer mesh but there is not any other change in solver settings...everything the same just better mesh and it always blows up.
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Old   September 10, 2021, 10:41
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Lucky
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Time step size...?

Are you already aware of the CFL condition? If all settings are the same (same time-step size) and you go to a finer mesh, it'll blow up.
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Old   September 10, 2021, 18:33
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Lorenzo Galieti
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A ye, if you use the explicit solver you are bound by CFL criterions
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bubble flow, fluent. convergence, vof multiphase

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