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

fvSchemes for Skewed and nonOrthogonal Mesh?

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

Like Tree2Likes
  • 1 Post By RodriguezFatz
  • 1 Post By Tushar@cfd

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 30, 2014, 06:53
Default fvSchemes for Skewed and nonOrthogonal Mesh?
  #1
New Member
 
Mubashir Ali
Join Date: Apr 2013
Location: India
Posts: 10
Rep Power: 12
mooby is on a distinguished road
Send a message via Skype™ to mooby
I have prepared a Mesh for a UAV using snappyHEX. the mesh passed the check mesh but highest non orthogonality is around 85 but average is pretty less and max skewness is 11. I wish to know what schemes I should be using to obtain acceptable results with this kind of mesh. I am using the default schemes settings in fv schemes
mooby is offline   Reply With Quote

Old   October 10, 2014, 14:35
Default
  #2
New Member
 
Join Date: Jul 2011
Posts: 9
Rep Power: 14
PHS- is on a distinguished road
85 seems pretty high so you should first try to decrease it in the mesh if you can.

Otherwise, you can try to set the laplacianSchemes to linear corrected or to linear limited 0.5

For more info on numerical schemes available, check out http://www.openfoam.org/docs/user/fvSchemes.php
PHS- is offline   Reply With Quote

Old   October 13, 2014, 07:51
Default
  #3
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 26
RodriguezFatz will become famous soon enough
You need "linear uncorrected" not "corrected" for the laplacian if the mesh is bad. Also, start with the safest (upwind) for all convective parts and "Euler" for ddt. "Gauss linear" for all gradients.
pavlossemelides likes this.
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   December 4, 2014, 10:25
Default fv-Schemes in general
  #4
Member
 
Tobias Adam
Join Date: Oct 2013
Location: Siegen
Posts: 55
Rep Power: 12
Tobias Adam is on a distinguished road
Hey everyone

I try to find an explantation to the fv-schemes.
I know how to use the main schemes. But I like to understand all schemes from this list.
Does anyone know where to find information about these.
Information could be anything like, the mathematical explanation the fv-schemes ( still I don´t understand c++) or descriptions about when to use which scheme.

The schemes I want to know about are listed in this document:

https://docs.google.com/document/d/1...it?usp=sharing

Tomorrow I´m going to ask someone to help me with C++, but I would be happy for each kind of information :-)

Best regards Tobi
Tobias Adam is offline   Reply With Quote

Old   December 4, 2014, 15:37
Default
  #5
Member
 
Hao Chen
Join Date: Aug 2014
Posts: 66
Rep Power: 0
hchen is on a distinguished road
Why when the mesh is bad Gauss uncorrected is needed?

Quote:
Originally Posted by RodriguezFatz View Post
You need "linear uncorrected" not "corrected" for the laplacian if the mesh is bad. Also, start with the safest (upwind) for all convective parts and "Euler" for ddt. "Gauss linear" for all gradients.
hchen is offline   Reply With Quote

Old   December 5, 2014, 00:54
Default
  #6
Senior Member
 
T. Chourushi
Join Date: Jul 2009
Posts: 321
Blog Entries: 1
Rep Power: 17
Tushar@cfd is on a distinguished road
Hello Everyone,

I think this problem is discussed many times on forum. The best answer for the same is answered in the following post:

http://www.cfd-online.com/Forums/ope...implefoam.html

For more information refer the weblink:

http://www.openfoam.org/docs/user/fvSchemes.php

-
Best Luck!
RodriguezFatz likes this.
Tushar@cfd is offline   Reply With Quote

Old   December 5, 2014, 03:19
Default
  #7
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 26
RodriguezFatz will become famous soon enough
But you need to pay attention in that link. They are talking about two different things. The first answer is about non-orthogonal correction of simple algorithm, which is indeed not needed for accuracy, if the solver converges.
Your question was about a correction of the laplace operator. This is something different. Just keep in mind that uncorrected is bounded and corrected is unbounded.
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Reply

Tags
openfoam

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
[snappyHexMesh] orthogonal cells marked as nonOrthogonal colinB OpenFOAM Meshing & Mesh Conversion 2 January 22, 2014 10:24
XiFoam floating point error..mut error? achinta OpenFOAM 8 July 31, 2012 05:48
fvScheme and NonOrthogonal Correctors Andrea_85 OpenFOAM 27 April 14, 2011 12:35
Circular Cylinder at low Reynold number mesh and non orthogonal corrections kassiotis OpenFOAM Running, Solving & CFD 6 May 15, 2008 07:07
When and how to apply nonOrthogonal correctors vvqf OpenFOAM Running, Solving & CFD 1 March 22, 2006 06:21


All times are GMT -4. The time now is 16:26.