CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > STAR-CCM+

Trimmer vs Polyhedral memory

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

Reply
 
LinkBack Thread Tools Display Modes
Old   November 15, 2012, 12:46
Default Trimmer vs Polyhedral memory
  #1
New Member
 
Christian Rodriguez
Join Date: Jan 2012
Posts: 9
Rep Power: 4
chris12345 is on a distinguished road
Hello,

I was wondering, I want to increase my overall background region mesh. I am though limitied my virtual memory, I usually use polyhedral but I am consedering using Trimmer cells.

My question now, which cell type takes more virtual/RAM memory? My aim is to refine my background mesh.

Thank you

//Chris
chris12345 is offline   Reply With Quote

Old   November 15, 2012, 18:58
Default
  #2
Senior Member
 
Join Date: Oct 2009
Location: Germany
Posts: 637
Rep Power: 12
abdul099 is on a distinguished road
The installation guide (can be found in the CCM+ directory) says:

Memory requirements for meshing:
Trimmed mesh: About 0.5 GB / million cells.
Polyhedral mesh: About 1GB / million cells.

Memory requirements for solving (serial, two-equation turbulence model, and I assume no multiphase flow, no energy equation, no chemical reaction etc...):

Polyhedral mesh:
Segregated: ~1GB / million cells
Coupled explicit: ~ 2GB / million cells
Coupled implicit: ~ 4GB / million cells

Trimmed mesh:
Segregated: ~0.5GB / million cells
Coupled explicit: ~ 1GB / million cells
Coupled implicit: ~ 2GB / million cells

I can confirm the requirements for meshing, solving segregated schemes and solving coupled implicit on trimmed meshed. The other schemes haven't been tested by me, but I assume it's close to reality.

So when you're tight on memory, a trimmed mesh with segregated solver seems to be the best choice - as long as your physics is suitable to run on a trimmed mesh (sometimes a polyhedral mesh could be better, especially when your flow is not aligned to your mesh lines).
__________________
We do three types of jobs here:
GOOD, FAST AND CHEAP
You may choose any two!
abdul099 is offline   Reply With Quote

Old   November 16, 2012, 04:48
Default
  #3
New Member
 
Christian Rodriguez
Join Date: Jan 2012
Posts: 9
Rep Power: 4
chris12345 is on a distinguished road
thanks for the reply abdul.

Im actually doing a study on a hovering helicopter. Im thinking of using polyhedral cells on my overset region (the main rotor) and the background region I'm thinking of using trimmed cells.

I want to use polyhedral cells but I need more cells around my wake, but I cant since im contrained over my memory usage.

What do you think about this set up?

//Chris
chris12345 is offline   Reply With Quote

Reply

Tags
memory, polyhedral, trimmer

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
partitioning memory keeper CFX 4 November 22, 2011 18:28
trimmer mesh vs Polyhedral mesh Marcelo CD-adapco 1 May 1, 2009 11:31
Memory error? Young CFX 3 September 30, 2008 11:33
CFX CPU time & real time Nick Strantzias CFX 8 July 23, 2006 17:50
Run-Time memory conifguration Error Graeme CFX 1 February 20, 2006 23:04


All times are GMT -4. The time now is 08:23.