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April 3, 2013, 03:29 

#21 
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B T KANNAN
Join Date: Jul 2011
Location: CHENNAI (MADRAS), INDIA
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Dear Vishal,
We are assuming wedge as an approximation to simplify the domain. KANNAN 

April 4, 2013, 00:15 

#22 
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Vishal Nandigana
Join Date: Mar 2009
Location: Champaign, Illinois, U.S.A
Posts: 208
Rep Power: 9 
You are right :P... was just curious why it was thought about to construct the geometry in this manner . The geometry works fine. Thanks for your tips.


April 5, 2013, 14:16 

#23  
Senior Member
Vishal Nandigana
Join Date: Mar 2009
Location: Champaign, Illinois, U.S.A
Posts: 208
Rep Power: 9 
Quote:
I am now modeling a concentric pipe geometry. I have difficulty in understanding which faces I should generate the mesh. I would like to give boundary conditions on both the surface of inner pipe and on the outer pipe. Here is the sample blockmesh dict file that I have generated. // length of pore = 36 nm and diameter: 10.2nm , theta = 2 deg (consider this as outer pipe) // length of DNA = 36 nm and diameter of DNA: 2.2nm , theta = 2 deg (consider this as inner pipe) //r_DNA*cos(theta/2) = 1.1*cos(0.0349/2 radians) = 1.0998 // r_DNA*sin(theta/2) = 1.1*sin(0.0349/2 radians) = 0.0192 //r_pore*cos(theta/2) = 5.1*cos(0.0349/2 radians) = 5.0992 //r_pore*sin(theta/2) = 5.1*sin(0.0349/2 radians) = 0.0890 vertices ( (0 0 0) // vertex 0 (36 0 0) // vertex 1 (36 1.0998 0.0192) // vertex 2 (L,r_DNA*cos(theta/2),r_DNA*sin(theta/2)) (0 1.0998 0.0192) // vertex 3 (0,rcos(theta/2),rsin(theta/2)) (36 5.0992 0.0890) // vertex 4 (L,r_pore*cos(theta/2),r_pore*sin(theta/2)) (0 5.0992 0.0890) // vertex 5 (0,r_pore*cos(theta/2),r_pore*sin(theta/2)) (0 0 0.0192) // vertex 6 (0, 0,r_DNA*sin(theta/2)) (36 0 0.0192) // vertex 7 (L, 0,r_DNA*sin(theta/2)) (36 1.0998 0.0192) // vertex 8 (0, r_DNA*cos(theta/2),r_DNA*sin(theta/2)) (0 1.0998 0.0192) // vertex 9 (L, r_DNA*cos(theta/2),r_DNA*sin(theta/2)) (0 0 0.0890) // vertex 10 (0, 0,r_pore*sin(theta/2)) (36 0 0.0890) // vertex 11 (L, 0,r_pore*sin(theta/2)) (36 5.0992 0.0890) // vertex 12 (L,r_pore*cos(theta/2),r_pore*sin(theta/2)) (0 5.0992 0.0890) // vertex 13 (0,r_pore*cos(theta/2),r_pore*sin(theta/2)) ); Please let me know if the vertices are correct. If so, how to generate the mesh for the same. Thanks Regards Vishal 

February 23, 2015, 11:30 

#24 
Member
Naresh Yathuru
Join Date: Feb 2015
Posts: 54
Rep Power: 2 
hi thanks every one for posting the reply. i have a question i would like to simulate a steady state simulate in ico foam so i changed to
ddtScheme { type steadystate; } Then i got this error FOAM Warning : From function gaussConvectionScheme in file finiteVolume/convectionSchemes/gaussConvectionScheme/gaussConvectionScheme.H at line 123 Reading "/home/yathuru/task1steady/system/fvSchemes.divSchemes.div(phi,U)" at line 31 Unbounded 'Gauss' div scheme used in steadystate solver, use 'bounded Gauss' to ensure boundedness. To remove this warning switch off 'boundedGauss' in "/opt/OpenFOAM2.3.0/etc/controlDict". can some one help me.. i m lost. 

February 23, 2015, 11:59 

#25 
Senior Member

Hi,
icoFoam is a transient solver. If you need steady state, simpleFoam is probably what you need. Regards, Jose 

February 25, 2015, 06:57 

#26  
Senior Member
Tushar Chourushi
Join Date: Jul 2009
Location: IITIndore, India
Posts: 319
Blog Entries: 1
Rep Power: 9 
Quote:
It's just a warning I guess you can run your case with that. OR, you can remove the warning as follows: Code:
divSchemes { ... bounded Gauss upwind; ... } Best Regards! 

March 2, 2015, 05:03 

#27 
Member
Naresh Yathuru
Join Date: Feb 2015
Posts: 54
Rep Power: 2 
Thank you so much for your reply santos and tushar. I knew i can do it in simple foam but just out of curiosity i wanted to try it in ico foam. I ran the simulation in simple foam its working well then i changed the case to turbulent simulation its is also working well now. however i have some issues with the convergence. i will try to figure it out. if not i will get back again .


March 2, 2015, 06:42 

#28  
Senior Member
Tushar Chourushi
Join Date: Jul 2009
Location: IITIndore, India
Posts: 319
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Quote:
Please refer my previous post again. I said that you can run your icofoam solver using the steady state command. Anyways I am writing these again: Code:
ddtScheme { type steadystate; } divSchemes { div(phi,U) bounded Gauss upwind; ... } 

March 2, 2015, 11:17 

#29 
Member
Naresh Yathuru
Join Date: Feb 2015
Posts: 54
Rep Power: 2 
Thanks once again Tushar. I m afraid if i can post this question here.
could you please give me some tips for which solver to use for this case below: Geometry : a room with a box inside. the room has a inlet and outlet. I want to simulate the flow through this room with some velocity and temperature at the inlet, the roof is maintained at a low temperature (20 C) and the box inside is maintained at a temperature (35C). could you please suggest a solver. 

March 3, 2015, 00:11 

#30  
Senior Member
Tushar Chourushi
Join Date: Jul 2009
Location: IITIndore, India
Posts: 319
Blog Entries: 1
Rep Power: 9 
Quote:
I will prefer you to go for "BuoyantBoussinesqPisoFoam", this will do the job. Wish you Good Luck for your work.  Best Regards! 

March 3, 2015, 03:12 

#31 
Member
Naresh Yathuru
Join Date: Feb 2015
Posts: 54
Rep Power: 2 
Thank you once again for your continuous support. U have no idea how much this tipp mean to me. thanks.


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