CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Native Meshers: snappyHexMesh and Others

A DMZ for snappyHexMesh

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

Like Tree2Likes
  • 1 Post By SirWombat
  • 1 Post By SirWombat

Reply
 
LinkBack Thread Tools Display Modes
Old   September 19, 2012, 20:19
Default A DMZ for snappyHexMesh
  #1
New Member
 
Conn Clark
Join Date: Dec 2010
Posts: 11
Rep Power: 5
ConnClark is on a distinguished road
Hello,

I have been meshing with some large meshes (at least for my laptop) and have about 6GB of data swapped out before snappyHexMesh starts eliminated mesh cells that are in enclosed surfaces. Is there a way to designate a Don't Mesh Zone to tell sHM not to bother with refining or meshing in volume before it gets to the point of eliminating cells in an enclosed surface? (if not it would be a nice feature to save time meshing )


Thank You

Conn
ConnClark is offline   Reply With Quote

Old   September 20, 2012, 04:23
Default
  #2
Member
 
Jan
Join Date: Dec 2009
Location: Berlin
Posts: 50
Rep Power: 8
SirWombat is on a distinguished road
Send a message via Skype™ to SirWombat
Here's an idea: you could use a "coarse" snappyHexMeshDict with a smaller surface than the original one. Then use your "fine" snappyHexMeshDict on that mesh. This will only work, if all of the "fine" surfaces is still inside a mesh region. Otherwise snappy won't snap at all.
ConnClark likes this.
__________________
~~~_/)~~~
SirWombat is offline   Reply With Quote

Old   September 20, 2012, 04:29
Default
  #3
Member
 
Jan
Join Date: Dec 2009
Location: Berlin
Posts: 50
Rep Power: 8
SirWombat is on a distinguished road
Send a message via Skype™ to SirWombat
just tried it with my setup, 'cause I really like the idea of saving memory and time!!

for the coarse mesh (snappyHexMeshDict_coarse):
Code:
castellatedMesh true;
snap            false;
addLayers       false;
then turn all your surface refinements to "0" and delete all refinementRegions.

for the fine mesh (snappyHexMeshDict_fine):
just take you original snappyHexMeshDict.


I used the following script "fastermesh.sh"
Code:
#!/bin/sh
cp system/snappyHexMeshDict_coarse system/snappyHexMeshDict
blockMesh
snappyHexMesh -overwrite
cp system/snappyHexMeshDict_fine system/snappyHexMeshDict
snappyHexMesh -overwrite

Seems to work very well in my case.


Greetings,
Jan
ConnClark likes this.
__________________
~~~_/)~~~
SirWombat is offline   Reply With Quote

Old   September 20, 2012, 18:56
Default
  #4
New Member
 
Conn Clark
Join Date: Dec 2010
Posts: 11
Rep Power: 5
ConnClark is on a distinguished road
Thank You, That helped a lot!!

Conn
ConnClark is offline   Reply With Quote

Old   September 21, 2012, 12:58
Default
  #5
New Member
 
Conn Clark
Join Date: Dec 2010
Posts: 11
Rep Power: 5
ConnClark is on a distinguished road
Oops,

I spoke too soon. After looking at the simulation data something wasn't right. The Mercedes I was simulating has been turned into a rice-boy neo-cubist car. The coefficient of lift is an impressive value of 1.4 . I don't think anybody has achieved that in auto design before.

back to swapping to disk.
ConnClark 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



All times are GMT -4. The time now is 19:56.