[tang17433]

Hi,
I used VOF did some work about bubble rising. But find some problem: when bubble's dimension is small(like 1mm or 1.5mm), the result seems not right. And i did bigger dimension(like 2mm or 3mm),the result seems well. I don't know why. The wrong situation picture showed here.

Regards,
Tang.

[Ahmed Alkaisi]

It seems to me like a mesh problem

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[tang17433]

Originally Posted by Ahmed Alkaisi

It seems to me like a mesh problem

Sent from my SM-G900I using CFD Online Forum mobile app

The mesh of D=1mm and D=2mm is the same as D=2mm. The only diffience is the scale。 And I increase the mesh 'density, it seems have no work. Here is the picture.

Did I get thing thing wrong?

I use VOF ,Implict Body Foce, Tension=0.072, presure outlet....

[hospital0968]

1. try to reduce the time-step and mesh size
2. try to change momentum method to 2 order upwind in the "solution method"

[tang17433]

Originally Posted by hospital0968

1. try to reduce the time-step and mesh size
2. try to change momentum method to 2 order upwind in the "solution method"

I reduce the time_step, and it works well. Thank you very much!