CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

Different patch type specifications for velocity and temperature

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   May 22, 2006, 14:20
Default Hi, Is there a way to speci
  #1
Member
 
Ankur Gupta
Join Date: Mar 2009
Posts: 38
Rep Power: 8
ankgupta8um is on a distinguished road
Hi,

Is there a way to specify a cyclic boundary condition to a pair of external surfaces for hydrodynamic quantities (i.e., velocity and pressure) and fixedValue/zeroGradient BC to the same pair of external surfaces for temperature ??
Any help would be highly appreciated.

Thanks!
Regards,
Ankur
ankgupta8um is offline   Reply With Quote

Old   May 22, 2006, 14:30
Default Hi, I am basically solving
  #2
Member
 
Ankur Gupta
Join Date: Mar 2009
Posts: 38
Rep Power: 8
ankgupta8um is on a distinguished road
Hi,

I am basically solving a channel flow and am using channelOodles solver. I would like to impose a cyclic boundary condition for velocity and pressure at channel inlet and outlet boundaries, and fixedvalue at inlet and zeroGradient at outlet for temperature.
Please help me as to how can I go about setting up my case.

Thanks!
Regards,
Ankur
ankgupta8um is offline   Reply With Quote

Old   May 23, 2006, 04:09
Default Never tried this but can you h
  #3
Super Moderator
 
Mattijs Janssens
Join Date: Mar 2009
Posts: 1,416
Rep Power: 16
mattijs is on a distinguished road
Never tried this but can you have your polyPatch type cyclic and some b.c.s cyclic and some fixedValue or zerogradient?

Or do the fixedValue/zeroGrad b.c.s then complain about not being on a plain patch but on a cyclic patch?
mattijs is offline   Reply With Quote

Old   May 23, 2006, 05:17
Default This is not easy to do. Cyclic
  #4
Senior Member
 
Eugene de Villiers
Join Date: Mar 2009
Posts: 725
Rep Power: 12
eugene is on a distinguished road
This is not easy to do. Cyclics are a base type and all corresponding patch fields need to be derived from that type. Thus you cannot use cyclics types in combination with patch types.

Here are some possible workarounds though:

1) Use normal inlet and outlet patches, i.e. fixedValue velocity and zeroGradient pressure at the inlet and zeroGradient velocity and fixedValue pressure at the outlet. Then have a look at the patch mapping routines in lesInterFoam from OF1.2 or earlier. You can use these mapping functions to map the outlet velocity to the inlet and the inlet pressure to the outlet. Of course accuracy will suffer somewhat and it will have problems in parallel unless you are careful.

2)Derive a new boundary condition from cyclic and override the evaluate function from coupledFvPatch using the zeroGradient condition instead of using the built-in cyclic evaluation. This might be quite tricky though as cyclics have quite a few unusual functions that you might have to override. Also, when running in parallel cyclics can become processor boundaries. This will probably play havoc with

3) (And this is a long shot) Find out why and where the code prevents the combination of cyclics and patch types and modify it to suite your needs.
eugene is offline   Reply With Quote

Old   May 23, 2006, 10:51
Default Thanks Eugene and Mattijs.
  #5
Member
 
Ankur Gupta
Join Date: Mar 2009
Posts: 38
Rep Power: 8
ankgupta8um is on a distinguished road
Thanks Eugene and Mattijs.
I already tried using cyclic base type in combination with patch types, and as Euegene pointed out, it didn't work.
I am focusing on the workarounds suggested by Eugene.


Thanks!
Regards,
Ankur
ankgupta8um is offline   Reply With Quote

Old   December 31, 2010, 11:57
Default
  #6
Senior Member
 
Nima Sam
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,123
Blog Entries: 1
Rep Power: 14
nimasam is on a distinguished road
Send a message via Yahoo to nimasam
hi friend
now i encounter the same problem, could you over come ur problem?
i have cyclic patch for U and P , and i like to have a boundary like
dT/dx inlet = dT/dx outlet for temperature
nimasam is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to read the patch type diegon OpenFOAM Running, Solving & CFD 0 January 10, 2007 16:03
Patch type Inlet boundary condition susana OpenFOAM Running, Solving & CFD 0 November 29, 2006 10:09
Temperature specifications Vidya Raja FLUENT 1 October 24, 2005 01:30
patch type cfd200 Phoenics 1 September 15, 2003 09:26
Temperature Patch Problem Prateep Chatterjee FLUENT 1 April 11, 2000 06:04


All times are GMT -4. The time now is 00:36.