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December 14, 2012, 11:24 |
Problem in multiphase Simulation
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#1 |
Member
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Dear friends
Hi I couldn't model flow in pipe correctly and as you can see in the pictures attached, depth of flow increases as time passes. It is impossible in reality. I really test a lot of ways to overcome this problem but I didn't succeed. Now I'm in pressure because of my results and lack of time. Thanks in Advance |
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December 15, 2012, 09:28 |
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#3 |
Member
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Dear Anton, thanks for your reply
I use salome for meshing. As you can see in the picture attached here I have to mesh both pipe and connected box. I've tried a lot of way to use hexa mesh but I didn't succeed due to this combination of pipe and box. Do you know exactly why this event happen? What should I do to overcome the problem in meshing? |
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December 15, 2012, 13:42 |
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#4 |
Retired Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
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Greetings to all!
@MOHAMMAD67, I'm sorry to say that I'm only able to give some hints:
Bruno
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Last edited by wyldckat; December 16, 2012 at 06:21. Reason: typo... |
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December 16, 2012, 05:01 |
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#5 |
Senior Member
Karl-Johan Nogenmyr
Join Date: Mar 2009
Location: Linköping
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Are you really sure it is unphysical? Is it steady state? If so, you can integrate (in paraview) mass flow across intersections to see if you really loose mass. The water depth level alone cannot tell, as mass flow through a pipe intersection is: area(depth) * U(x,y,z)
K |
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December 16, 2012, 12:20 |
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#6 | |
Senior Member
Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
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Quote:
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December 16, 2012, 13:30 |
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#7 | |
Member
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Quote:
I also model it experimentally and I haven't see such a these phenomenon. This event change for each flowrate. for example in a particular case with constatnt mesh, for Q=25 l/s pipe will be pressurized!!! but for an upper Q just increase in water depth happened. Could it be related to boundary conditions? I use an air inlet in the upstream end of the pipe and atmosphere for upper wall of the box. However, I think here mesh is very important and I'm really interested in hex mesh for upstream pipe. Is there an easy way to do this nothing that I haven't work with snappy hex mesh yet.? |
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December 16, 2012, 14:17 |
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#8 |
Senior Member
Nima Samkhaniani
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Location: Tehran, Iran
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is it a steady solution?
yes, it is possible to use snappyHexMesh for generate hex mesh for this geometry
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December 16, 2012, 14:29 |
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#9 | |
Member
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Quote:
Salaam Water depth in the upstream pipe reaches steady state but generally it's a transient problem. I've searched about snappyhexmesh today. But I couldn't understand how I can create geometry with .stl format. Does it need another software? |
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December 16, 2012, 15:38 |
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#10 |
Senior Member
Nima Samkhaniani
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Location: Tehran, Iran
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as your geometry is not so complicated, i guess you can make stl file even with paraview (maybe seems strange)
also i think you can do it even with out stl, file, i think you need to dig more snappyHexMesh in OpenFOAM
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December 21, 2012, 14:27 |
Problem of meshing solved but depth increasing is still seen
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#11 |
Member
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Dear Friend
Fortunately, My problem related to use hexahedral mesh has been solved with the help of my friend Saint Michael in Salome forum. If you are interested, you can see this page: http://www.salome-platform.org/forum/forum_10/61041109 But my problem is still seen!! I don't know what to do? please help Best Wishes |
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December 21, 2012, 16:16 |
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#12 |
Senior Member
Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
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some general recommendations:
1- in fvSolution, turn on momentom prediction 2- increase alpha correction 3- increase non-orthogonality correction
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Tags |
multiphase flow, pipe flow |
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