Multiphase VOF Taylor bubbles

Dominab · September 10, 2021, 09:18

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.

LuckyTran · September 10, 2021, 10:41

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.

LoGaL · September 10, 2021, 18:33

A ye, if you use the explicit solver you are bound by CFL criterions

September 10, 2021, 10:41		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 66	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. Dominab likes this.

September 10, 2021, 18:33		#3
LoGaL Senior Member Lorenzo Galieti Join Date: Mar 2018 Posts: 373 Rep Power: 12	A ye, if you use the explicit solver you are bound by CFL criterions Dominab likes this.

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