# Closed tank and interFoam

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 September 17, 2013, 13:13 Closed tank and interFoam #1 Super Moderator     Tobias Holzmann Join Date: Oct 2010 Location: Leoben (Austria) Posts: 1,843 Blog Entries: 6 Rep Power: 32 Sponsored Links Hi all, just a question to all who are using interFoam. I made a lot of simulations with that solver but never with a closed tank or something like that. My idea was to create a tank with p=101300 Pa in it. I have one inlet and the rest are walls. Now I want that a fluid (water) gets into the tank with 200000 Pa. Normally the water get in the tank till the compressed air has exact 200000Pa. The problem I have is to set correct BC for that. Or is it possible to calculate this problem with cfd? Due to the fact of momentum equation ... mass is going into the system but not out of the system! Thanks in advance Tobi

 September 17, 2013, 14:04 #2 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,216 Blog Entries: 1 Rep Power: 17 well, i guess interFoam is not suitable as it consider both phases incompressible, you may want to use compressibleInterFoam Poltak Stanggang and Tobi like this. __________________ Telegram channel (https://telegram.me/openfoam4Iranian) My Weblog in Persian(http://openfoam.blogfa.com/) My Personal Website (http://nimasamkhaniani.ir/)

September 17, 2013, 14:35
#3
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Tobias Holzmann
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Quote:
 Originally Posted by nimasam well, i guess interFoam is not suitable as it consider both phases incompressible, you may want to use compressibleInterFoam
Oh thanks for that hint
thats sure!

I will test it!

 September 17, 2013, 16:13 #4 Super Moderator     Tobias Holzmann Join Date: Oct 2010 Location: Leoben (Austria) Posts: 1,843 Blog Entries: 6 Rep Power: 32 Hi, okay the solver is running. But I am not sure how I should set the BC for the inlet? As I mentioned in the first post, the water should go inside with 2 bar while the air is with 1 bar. After compression of air to 2bar no water is going into the tank.

 September 18, 2013, 00:55 #5 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,216 Blog Entries: 1 Rep Power: 17 well, i guess i use pressureInletVelocity , then i will fix pressure at inlet please share the result here __________________ Telegram channel (https://telegram.me/openfoam4Iranian) My Weblog in Persian(http://openfoam.blogfa.com/) My Personal Website (http://nimasamkhaniani.ir/)

 September 19, 2013, 07:05 #6 Super Moderator     Tobias Holzmann Join Date: Oct 2010 Location: Leoben (Austria) Posts: 1,843 Blog Entries: 6 Rep Power: 32 Hi all, well my first quess was to set U to pressureInletVelocity and p to fixedValue like you mentioned. But it is not working. The simulations is total unphysical and I got an Floating Point exeption. First: p_inlet = 2 bar P_internalField = 1 bar Second: p_inlet = 1.005 bar p_internalField = 1 bar (Nothing changed) hmmm any hints are appreciate

 September 19, 2013, 07:18 #7 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,216 Blog Entries: 1 Rep Power: 17 at least post the error file , and your setup here __________________ Telegram channel (https://telegram.me/openfoam4Iranian) My Weblog in Persian(http://openfoam.blogfa.com/) My Personal Website (http://nimasamkhaniani.ir/)

 September 19, 2013, 08:48 #8 Super Moderator     Tobias Holzmann Join Date: Oct 2010 Location: Leoben (Austria) Posts: 1,843 Blog Entries: 6 Rep Power: 32 Hi, I will do it today evening.

 September 19, 2013, 16:47 #9 Super Moderator     Tobias Holzmann Join Date: Oct 2010 Location: Leoben (Austria) Posts: 1,843 Blog Entries: 6 Rep Power: 32 Here the U - file: Code: ```boundaryField { wall { type fixedValue; value uniform (0 0 0); } inlet { type pressureInletVelocity; value uniform (0 0 0); } }``` and the p_rgh file Code: ```boundaryField { wall { type fixedFluxPressure; value uniform 1e5; } inlet { type fixedValue; value uniform 1.01e5; } }```

 September 20, 2013, 02:40 #10 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,216 Blog Entries: 1 Rep Power: 17 1- whats your alpha1 file? 2- how is your initial setup? 3-how is your mesh? 4-which version of OF do you use? __________________ Telegram channel (https://telegram.me/openfoam4Iranian) My Weblog in Persian(http://openfoam.blogfa.com/) My Personal Website (http://nimasamkhaniani.ir/)

 September 20, 2013, 06:24 #11 Super Moderator     Tobias Holzmann Join Date: Oct 2010 Location: Leoben (Austria) Posts: 1,843 Blog Entries: 6 Rep Power: 32 Hi, initialValues: Code: ``` p = 1e5 (boundary = calculated) p_rgh = 1e5 U = (0 0 0) alphaWater = 0 (boundary = ZeroGradient for the wall and inlet = fixedValue = 1) T = 300 (boundary = zeroGradient; inlet 300 fixed)``` Mesh is a cube 0,5 x 0,5 x 0,5 m with round about 200.000 cells (not many but okay). The inlet is a extra cube with 0,05 x 0,05 x 0,05 m. Mesh made with salome only Hexaeder cells. I think alphaWater = 1 = phase1 (water) and alphaWater = 0 = phase2 (air) I use always the latest OpenFOAM Version (2.2.x).

 September 20, 2013, 06:36 #12 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,216 Blog Entries: 1 Rep Power: 17 what about air and water properties , how did you setup transportproperties? __________________ Telegram channel (https://telegram.me/openfoam4Iranian) My Weblog in Persian(http://openfoam.blogfa.com/) My Personal Website (http://nimasamkhaniani.ir/)

 September 20, 2013, 06:45 #13 Super Moderator     Tobias Holzmann Join Date: Oct 2010 Location: Leoben (Austria) Posts: 1,843 Blog Entries: 6 Rep Power: 32 Hi, well I do not have a look at that file since now. I copied the tutorial of the compressibleInterFoam solver. I thought that there is water and air included? I will have a look at that file today evening. Question to you - did you ever simulated a closed tank or something like that?

September 20, 2013, 08:38
#14
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Nima Samkhaniani
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Quote:
 Originally Posted by Tobi Hi, well I do not have a look at that file since now. I copied the tutorial of the compressibleInterFoam solver. I thought that there is water and air included?
well, perfect simulation :P

Quote:
 Originally Posted by Tobi I will have a look at that file today evening. Question to you - did you ever simulated a closed tank or something like that?
nope, i never did, but as it compressible, for me those configuration seems okay
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 September 20, 2013, 13:07 #15 Super Moderator     Tobias Holzmann Join Date: Oct 2010 Location: Leoben (Austria) Posts: 1,843 Blog Entries: 6 Rep Power: 32 Hi, as I thought everything is correct! phase1 = water; phase2 = air.

September 22, 2013, 07:45
#16
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Tobias Holzmann
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Okay its working now.

But one thing is still strange (attachment)...

Does anyone know why I have so strange gradients in alpha1 ?
Attached Images
 alpha#.jpg (26.7 KB, 23 views)

 September 23, 2013, 02:36 #17 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,216 Blog Entries: 1 Rep Power: 17 well 1- how did you solve your first problem (float exception?) 2- whats wrong with alpha1 gradient? distribution seems OK with me __________________ Telegram channel (https://telegram.me/openfoam4Iranian) My Weblog in Persian(http://openfoam.blogfa.com/) My Personal Website (http://nimasamkhaniani.ir/)

 September 23, 2013, 02:45 #18 Super Moderator     Tobias Holzmann Join Date: Oct 2010 Location: Leoben (Austria) Posts: 1,843 Blog Entries: 6 Rep Power: 32 Hi, I thought that I solved the first problem but with a p_rgh of 2 bar at the inlet its not working anymore. Hmmm ... I am out of mind and it is so a simple geometry... hmmm Last edited by Tobi; September 23, 2013 at 06:34.

 September 23, 2013, 10:37 #19 New Member   Join Date: Sep 2012 Posts: 23 Rep Power: 6 don't mind to hijack this thread, but can anyone assist me here too: http://www.cfd-online.com/Forums/ope...modelling.html my problem seems easier to solve compared to the one here.

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