
[Sponsors] 
April 3, 2013, 03:29 

#21 
Member
B T KANNAN
Join Date: Jul 2011
Location: CHENNAI (MADRAS), INDIA
Posts: 54
Rep Power: 7 
Dear Vishal,
We are assuming wedge as an approximation to simplify the domain. KANNAN 

April 4, 2013, 00:15 

#22 
Senior Member
Vishal Nandigana
Join Date: Mar 2009
Location: Champaign, Illinois, U.S.A
Posts: 208
Rep Power: 10 
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: 10 
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: 59
Rep Power: 3 
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: 10 
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: 59
Rep Power: 3 
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
Blog Entries: 1
Rep Power: 10 
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: 59
Rep Power: 3 
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: 10 
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: 59
Rep Power: 3 
Thank you once again for your continuous support. U have no idea how much this tipp mean to me. thanks.


Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
SimpleFoam unable to reach steady state  francois  OpenFOAM Running, Solving & CFD  8  November 19, 2009 14:33 
plz help,urgent, vof model steady state  Garima Chaudhary  FLUENT  2  May 30, 2007 04:38 
steady state, laminar vof_model  Garima Chaudhary  FLUENT  0  May 24, 2007 03:11 
Flow laminar and stationary of water in a pipe  manuel  OpenFOAM Running, Solving & CFD  6  March 24, 2007 19:23 
buoyancy driven flow in steady state in CFX4.3  raymondyin  CFX  11  May 7, 2001 06:15 