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BC for a water-air system

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Old   February 20, 2017, 04:30
Default BC for a water-air system
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Hi everybody!

the aim of my simulation is to evaluate the interaction in between a flux of air through a flux of water, like in the picture-1 attached.

The solver I'm using is interFoam and the tutorial I used to start is damBreak.
First I tried to implement the inlet flow of water , with turbulent condition, without air flux, and I expanded the volume of study

The boundary conditions I applied are as in the attached files ( I choose them based on those of the damBreak tutorial and from a tutorial at this page:

What I get is an error about the number of iterations, as in the attached file ( The log file is shorter than the real one beacause of file dimension.

So, which should be in general the correct (or standard) BC for a simulation like this (and with the air-flux applied)?

Thanks in advance for any kind reply.

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File Type: zip (47.8 KB, 10 views)

Last edited by iopenfoam; February 20, 2017 at 05:01. Reason: Clarification
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Old   February 20, 2017, 06:39
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It looks like you used a fixed time step, which causes the courant number to increase too much.

Set adjustTimeStep to "yes" and max courant number to 0.5 in your controldict and it should be better.
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Old   February 22, 2017, 03:21
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Hi Sati,

thanks for your hint, it works fine now!
I guess the problem was about a high velocity of the fluid while falling, so with high velocity , but same time step and cell size, the Courant number increased too much and affected convengence.

Thanks a lot!

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