CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > ANSYS Meshing & Geometry

[GAMBIT] How to set up sizing function where there is a large transition in grid sizes

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 11, 2015, 01:03
Default How to set up sizing function where there is a large transition in grid sizes
  #1
New Member
 
gautham narayan
Join Date: Apr 2015
Posts: 16
Rep Power: 11
gauthamnarayan is on a distinguished road
I am trying to mesh a slightly complicated 2d geometry in gambit. I am facing problems while using the pave method to generate unstructured quads.

I am not able to post the geometry here, so I will provide the description about a part of the geometry that can be easily understood. |I am facing problems only in this region.

Consider a rectangular domain height = 10000 width =20000. node distribution on bottom face = first length 1, number of nodes = 500, node distribution on left face = first length = 40 number of nodes =50.

I need to mesh this domain using the pave method using the least number of cells as possible as not much flow physics is expected here. I have tried using various values in sizing functions, I have not been to able to successfully mesh it.

Anyone who can provide any clues to how to set up an acceptable sizing function is very much appreciated.
gauthamnarayan is offline   Reply With Quote

Old   December 11, 2015, 02:36
Default
  #2
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
create a size function with meshed option
select both mesh edges as source and your face as attachment.
grow factor 1.2 for example and max size 1000
adapt those 2 parameters
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   December 11, 2015, 02:54
Default
  #3
New Member
 
gautham narayan
Join Date: Apr 2015
Posts: 16
Rep Power: 11
gauthamnarayan is on a distinguished road
Quote:
Originally Posted by -mAx- View Post
create a size function with meshed option
select both mesh edges as source and your face as attachment.
grow factor 1.2 for example and max size 1000
adapt those 2 parameters
Dear Sir,

I have previously tried using size functions with the exact parameters mentioned with a start size of 40. Gambit fails to pave after 4700 cells.
Gambit suggests to adjust mesh sizes and try again.

I have tried several values of size functions. Not been able to pave successfully. I think due to the large edge growth rate in both directions, the algorithm has failed.

I have attempted several combinations including growth ratios from 1.05 till 1.95, none of them successful. Please let me know if there is a more methodological approach to determining the correct growth ratio, start size and max size.

Thank you for your help!
gauthamnarayan is offline   Reply With Quote

Old   December 11, 2015, 03:00
Default
  #4
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
just try with several parameters
there is no start size in the size function if you select the "meshed" type
Untitled.png
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   December 11, 2015, 03:39
Default
  #5
New Member
 
gautham narayan
Join Date: Apr 2015
Posts: 16
Rep Power: 11
gauthamnarayan is on a distinguished road
Quote:
Originally Posted by -mAx- View Post
just try with several parameters
there is no start size in the size function if you select the "meshed" type
Attachment 44032
Thank you very much sir. The mistake was that I was trying to use a fixed size function, due to this meshing failed.

For future cases and others who may view this thread, in case of meshing failing while paving or any other method, where the cells are generated in order of advancing front, is it possible to find out which region caused the mesher to stop? Is it possbile to view any file where the mesh is temporarily written and try to understand the problem.

Thank you,
gauthamnarayan is offline   Reply With Quote

Old   December 11, 2015, 03:45
Default
  #6
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41
-mAx- will become famous soon enough
the only info you can have will be displayed in the transcript windo (also *.tr file if I am right)
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Reply

Tags
gambit, grid generation


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
[Other] refineWallLayer Error Yuby OpenFOAM Meshing & Mesh Conversion 2 November 11, 2021 12:04
is internalField(U) equivalent to zeroGradient? immortality OpenFOAM Running, Solving & CFD 7 March 29, 2013 02:27
channelFoam for a 3D pipe AlmostSurelyRob OpenFOAM 3 June 24, 2011 14:06
Problem with rhoSimpleFoam matteo_gautero OpenFOAM Running, Solving & CFD 0 February 28, 2008 07:51
Grid Independent Solution Chuck Leakeas Main CFD Forum 2 May 26, 2000 12:18


All times are GMT -4. The time now is 07:04.