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-   -   Reversed flow in vof model or water damping (https://www.cfd-online.com/Forums/fluent/208122-reversed-flow-vof-model-water-damping.html)

David712 October 9, 2018 22:53

Reversed flow in vof model or water damping
 
I am trying to simulate an example for a flow around a circle based on a stratified circumstance which also contain the air in a planar. If I use a pressure outlet for the 'out', there are reversed flow finding in the outlet even I had tried to use an udf for the pressure.
Whats more, if I use an outflow for the 'out', no reversed flow would be found but the water near the 'out' seems to rise or damp maybe.
I want to know there is a way to avoid such kinds of 'mistakes' because no matter which kind of 'mistake' do effect the flow field of the simulation.

RaiderDoctor October 9, 2018 22:56

How close is your outlet to the cylinder? Can you post some pictures of the setup and solution (preferably with a contour map and velocity vectors shown). Finally, what does your mesh look like?

David712 October 9, 2018 23:29

http://a4.qpic.cn/psb?/a2e89427-7d40...=photolist&t=5
http://a1.qpic.cn/psb?/a2e89427-7d40...=photolist&t=5
http://a4.qpic.cn/psb?/a2e89427-7d40...=photolist&t=5
http://a4.qpic.cn/psb?/a2e89427-7d40...=photolist&t=5

The first picture is the wave-height for the surface flow(simulate a short time so the wave damping or rising is not obvious)
Second picture is the flow field of the circle;
Third picture is the mesh condition;
Fourth picture is the phase condition(three phase);

RaiderDoctor October 9, 2018 23:35

I can't open any of your photos. Make sure you save them in a good format (.png or .jpeg) and attach them by clicking "Manage Attachments" in the "Additional Options" section on the forum.


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