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

Boundary conditions for Staggered grid - steady pipe Flow - SIMPLE

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 3, 2021, 06:39
Post Boundary conditions for Staggered grid - steady pipe Flow - SIMPLE
  #1
New Member
 
Aman Sangal
Join Date: Mar 2021
Posts: 22
Blog Entries: 2
Rep Power: 5
Fluidentity13 is on a distinguished road
Hi everyone,

I'm sorry for yet another thread, but I am getting stuck pretty bad. I promise to upload all my notes, & proper documentation for devising a staggered solver with Steady & Unsteady problems from scratch.

For now, I am having trouble defining the boundary condition on a staggered grid. This is for a SIMPLE solver I am trying to create.
For a Staggered Model with Velocity grid encapsulating the Pressure grid fully, I am using the following boundary condition for pipe flow.
1. Ux = 1.0 West
2. Uy = 0.0 West
3. Ux[East] = Ux[East-1]
4. Uy[East] = Uy[East-1]
5. Uy[North] = 0
6. Uy[South] = 0
7. P[East] = 0
Please have a look at the annotated image too. I've disregarded gravity in the momentum predictor here, & used East column of Pressure = 0 B.C.


Are these minimal necessary boundary conditions implied onto the grid, or some of them can be removed?
Also, I'd appreciate any easy get arounds for implementing these boundary conditions, besides resizing the whole system of equation matrix.

Any documentation you can guide me toward for staggered boundary conditions would be marvellous, as I can't finding anything proper in patankar, Chowdhury, or peric.
Attached Images
File Type: jpg Boundary Conditions.jpg (153.4 KB, 25 views)
Fluidentity13 is offline   Reply With Quote

Old   November 4, 2021, 01:29
Default
  #2
New Member
 
Aman Sangal
Join Date: Mar 2021
Posts: 22
Blog Entries: 2
Rep Power: 5
Fluidentity13 is on a distinguished road
https://www.youtube.com/watch?v=hb4R...KB9aqT&index=4

This cleared all of my doubts. I wasn't discretising the diffusion term for boundary cell seperately, just using coefficients from generalised cell, which isn't a problem for the convective terms, but is a problem for diffusion terms.
Fluidentity13 is offline   Reply With Quote

Reply

Tags
boundary conditions, simple solver, singular matrix, 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
Adequate boundary conditions for compressible pipe flow chrisvolkmar Main CFD Forum 0 June 22, 2016 13:54
Wrong flow in ratating domain problem Sanyo CFX 17 August 15, 2015 07:20
Error finding variable "THERMX" sunilpatil CFX 8 April 26, 2013 08:00


All times are GMT -4. The time now is 09:35.