# Reversed flow in vof model or water damping

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 October 9, 2018, 21:53 Reversed flow in vof model or water damping #1 New Member   Join Date: Oct 2018 Posts: 17 Rep Power: 6 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.

 October 9, 2018, 21:56 #2 Senior Member   Join Date: Dec 2016 Posts: 152 Rep Power: 9 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?

 October 9, 2018, 22:29 #3 New Member   Join Date: Oct 2018 Posts: 17 Rep Power: 6 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);

 October 9, 2018, 22:35 #4 Senior Member   Join Date: Dec 2016 Posts: 152 Rep Power: 9 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.

 Tags reversed flow, vof modeling