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Natural Convection Simulation - buoyantSimpleRadiation - Convergence Problem |
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June 9, 2010, 08:24 |
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#21 |
Member
Francois Gallard
Join Date: Mar 2010
Location: Toulouse, France
Posts: 44
Rep Power: 16 |
Ok, that is what I thought.
Could you try to put fixedValue 100 000 at the bottom and zeroGradient at the top for the pressure boundary conditions ? The pressure is the motor of the flow with the buoyancy effect, as long as it is incorrect, the computation will not converge. Francois. |
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June 10, 2010, 02:55 |
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#22 |
Member
MSarkar
Join Date: Dec 2009
Posts: 99
Rep Power: 17 |
Hello Francois,
I tried that fixedValue 100 000 at bottom and zeroGradient at top but it did not give me any good results. The pressure and velocity fields are unrealistic. Pressure and velocity fields are attached below. I am trying some other pressure boundary conditions. If you have any other suggestions, please let me know. Thanks and Regards M. Sarkar |
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June 10, 2010, 05:51 |
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#23 |
Member
Francois Gallard
Join Date: Mar 2010
Location: Toulouse, France
Posts: 44
Rep Power: 16 |
Hello,
Could you please rescale the pressure field between 100 000 and 100 010 ? I have the impression that now the hydrostatic gradient is correct. You have something weird at the angle but that could come from something else. Could you share all your boundary, system and constant files ? Cheers, François |
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June 10, 2010, 07:21 |
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#24 |
Member
MSarkar
Join Date: Dec 2009
Posts: 99
Rep Power: 17 |
Hi,
Yes I can rescale the pressure field but there is a glitch in the corner and I guess because of that it is not predicting velocity and temperature fields correctly. Anyway I will rescale it and post it later. I am attaching the 0, constant and system files as you requested. If I am wrong anywhere, please let me know. Thanks M. Sarkar |
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June 10, 2010, 09:11 |
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#25 |
Senior Member
Arjun
Join Date: Mar 2009
Location: Nurenberg, Germany
Posts: 1,290
Rep Power: 34 |
Okay , i decided to add bouss. method to inavier just to see how your problem works.
Here are some plots after running with iNavier den = 1.225 Tref = 288 beta = 2.1E-4 visc = 1.789E-5 Temperature Pressure y vel I believe these results look alright because something similar i got from Fluent too. Please note that this is very first thing i ran with iNavier in name of bouss. model. So iNavier is not tested. About convergence, i noticed that normalised residual is not good idea in this case to judge about convergence because normalised residual work by deviding maximum error found in first 5 or 10 iterations. But in this case velocity field is zero in the start and there is no flow in or out. So initial abs residual is very low. Which increases with iterations and then fall down. |
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June 15, 2010, 06:18 |
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#26 |
Member
MSarkar
Join Date: Dec 2009
Posts: 99
Rep Power: 17 |
Hi Arjun,
I did not see any result files here. Could you please upload your results? Did you use OpenFOAM-1.6.x for this simulation? I am sorry, I did not understand what is that iNavier you mentioned? If you use OF-1.6.x, which solver did you use, buoyantSimpleRadiatioFoam or something else? |
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June 15, 2010, 10:36 |
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#27 | |
Senior Member
Arjun
Join Date: Mar 2009
Location: Nurenberg, Germany
Posts: 1,290
Rep Power: 34 |
Quote:
i uploaded it on flickr and probably that is not visible to you. Coudl you give me your email i will mail you tecplot file. |
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June 16, 2010, 03:08 |
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#28 | |
Member
MSarkar
Join Date: Dec 2009
Posts: 99
Rep Power: 17 |
Quote:
My email id is below, please send me the files. If it is possible, send me the files in .jpg or .png format. I do not have Techplot. Can I open the files you mentioned using paraview? You did not mention anything about the tool you used to simulate this problem. I guess you used OF-1.6.x. Last edited by msarkar; June 16, 2010 at 07:21. |
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June 16, 2010, 06:19 |
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#29 | |
Senior Member
Arjun
Join Date: Mar 2009
Location: Nurenberg, Germany
Posts: 1,290
Rep Power: 34 |
Quote:
i will email, it is on my other computer so might take a while. About tecplot, there is one beautiful tool people do not use: https://wci.llnl.gov/codes/visit/home.html download it for tecplot Files. I could send you paraview based files too but i export ensight gold format and somehow paraview goofs up when dealing with 2D data. In three D things seems to be alright. About tool i used (iNavier), it is just a small code i wrote this reads mesh files in fluent format and runs segreggated SIMPLE algorithm. I am working on releasing next version but still busy doing documentations etc etc. So still not in public domain. I will email you exe though, you could play with it. |
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June 16, 2010, 07:12 |
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#30 |
Senior Member
Arjun
Join Date: Mar 2009
Location: Nurenberg, Germany
Posts: 1,290
Rep Power: 34 |
i sent email , read the doc, please understand that solver is still under testing.
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June 16, 2010, 07:21 |
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#31 | |
Member
MSarkar
Join Date: Dec 2009
Posts: 99
Rep Power: 17 |
Quote:
Sorry to request you again. Please send me the files in my other email id. I did not receive your email. My company email system quarantined it as it contained an attachment which is against the company policy. email: mita.sarkar@gmail.com So you did not use OpenFOAM but anyway I can look at your results. |
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June 16, 2010, 07:23 |
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#32 | |
Senior Member
Arjun
Join Date: Mar 2009
Location: Nurenberg, Germany
Posts: 1,290
Rep Power: 34 |
Quote:
do you have anything other than gmail because my attachment contains exe and gmail does not allow it. This is why i do not use gmail. |
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June 16, 2010, 07:27 |
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#33 |
Member
Francois Gallard
Join Date: Mar 2010
Location: Toulouse, France
Posts: 44
Rep Power: 16 |
Hello,
I used second order schemes (Gauss linear for all div terms) and used 100x100 cells in your blocks instead of 50x50, used the same boundary conditions and get rid of that pressure problem. The results are still not ok because of the Epsilon equation but there is still some work to do. I keep you aware. Francois Francois |
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