CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > General Forums > Main CFD Forum

Periodic boundary conditions for velocity in Staggered grids

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 21, 2022, 05:45
Default Periodic boundary conditions for velocity in Staggered grids
  #1
Member
 
Divyaprakash
Join Date: Jun 2014
Posts: 74
Rep Power: 12
Divyaprakash is on a distinguished road
Hi,


I am trying to implement periodic boundary conditions along the x -direction. So far I am getting error in the approach I am using.
https://drive.google.com/file/d/1E_z...ew?usp=sharing



I want to confirm If I have correctly implement the BCs. I am attaching an image which shows how I have implemented periodicity.
The first grid corresponds to pressure.
The second grid corresponds to u-velocity.
The hatched lines indicate the periodic boundary.


Can someone confirm if this correct or correct them if wrong.

Last edited by Divyaprakash; August 21, 2022 at 05:46. Reason: image was not visible
Divyaprakash is offline   Reply With Quote

Old   August 21, 2022, 07:36
Default
  #2
Senior Member
 
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,893
Rep Power: 73
FMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura about
Quote:
Originally Posted by Divyaprakash View Post
Hi,


I am trying to implement periodic boundary conditions along the x -direction. So far I am getting error in the approach I am using.
https://drive.google.com/file/d/1E_z...ew?usp=sharing



I want to confirm If I have correctly implement the BCs. I am attaching an image which shows how I have implemented periodicity.
The first grid corresponds to pressure.
The second grid corresponds to u-velocity.
The hatched lines indicate the periodic boundary.


Can someone confirm if this correct or correct them if wrong.
Why the x-velocity is differently colocated along x?
FMDenaro is offline   Reply With Quote

Old   August 21, 2022, 09:37
Default
  #3
Member
 
Divyaprakash
Join Date: Jun 2014
Posts: 74
Rep Power: 12
Divyaprakash is on a distinguished road
The x velocity is forward staggered.
Divyaprakash is offline   Reply With Quote

Old   August 21, 2022, 10:09
Default
  #4
Senior Member
 
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,893
Rep Power: 73
FMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura about
I used your sketch to show the correct staggered colocation for all the u components superimposed to the pressure colocation.
However, you seems to show walls at the BCs, thus you cannot use periodicity.
Attached Images
File Type: jpg 69008.jpg (39.0 KB, 17 views)
FMDenaro is offline   Reply With Quote

Old   August 21, 2022, 10:36
Default
  #5
Member
 
Divyaprakash
Join Date: Jun 2014
Posts: 74
Rep Power: 12
Divyaprakash is on a distinguished road
Thank you so much for your time. Actually the ends are not walls. I used hatched lines, just to indicate boundaries. I am trying to simulate a 2D case with the top and bottom walls moving and the left and right boundaries periodic.


Can you please tell me in terms of the notations that you used in the figure, how may I apply the pressure and velocity boundary conditions? I have been stuck at this problem for quite long.

Last edited by Divyaprakash; August 21, 2022 at 10:38. Reason: More details
Divyaprakash is offline   Reply With Quote

Old   August 21, 2022, 12:30
Default
  #6
Senior Member
 
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,893
Rep Power: 73
FMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura about
Quote:
Originally Posted by Divyaprakash View Post
Thank you so much for your time. Actually the ends are not walls. I used hatched lines, just to indicate boundaries. I am trying to simulate a 2D case with the top and bottom walls moving and the left and right boundaries periodic.


Can you please tell me in terms of the notations that you used in the figure, how may I apply the pressure and velocity boundary conditions? I have been stuck at this problem for quite long.



The pressure notation you wrote is correct. The u-velocity periodicity needs to set u1=u6.
FMDenaro is offline   Reply With Quote

Old   August 21, 2022, 13:27
Default
  #7
Member
 
Divyaprakash
Join Date: Jun 2014
Posts: 74
Rep Power: 12
Divyaprakash is on a distinguished road
Quote:
Originally Posted by FMDenaro View Post
The pressure notation you wrote is correct. The u-velocity periodicity needs to set u1=u6.



But u1 and u6 both are unknown. How can I specify one as another?
Divyaprakash is offline   Reply With Quote

Old   August 21, 2022, 13:31
Default
  #8
Senior Member
 
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,893
Rep Power: 73
FMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura about
You have to compute the equation for one of them
FMDenaro is offline   Reply With Quote

Old   August 21, 2022, 13:44
Default
  #9
Member
 
Divyaprakash
Join Date: Jun 2014
Posts: 74
Rep Power: 12
Divyaprakash is on a distinguished road
Quote:
Originally Posted by FMDenaro View Post
You have to compute the equation for one of them

Thank you so much. I'll try to implement it.

Just one more question. I have seen in many places the BC being implemented as follows.
how to implement periodic bc on a staggered grid


Would this work too? Based on above I had implemented the BC in my original figure.
Divyaprakash is offline   Reply With Quote

Reply

Tags
periodic bc, staggered grid

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
3D Windturbine simulation in SU2 k.vimalakanthan SU2 15 October 12, 2023 06:53
Table bounds warnings at: END OF TIME STEP CFXer CFX 4 July 17, 2020 00:44
Can I achieve better convergence? sheaker CFX 12 September 19, 2019 16:36
Radiation in semi-transparent media with surface-to-surface model? mpeppels CFX 11 August 22, 2019 08:30
PEMFC module + multiple periodic boundary conditions vkrastev FLUENT 2 December 22, 2014 05:15


All times are GMT -4. The time now is 00:14.