CFD Online Discussion Forums

How to let the mesh motion solver just solve a small region near a moving boundary?

Posted October 8, 2012 at 21:34 by sunliming

Quote:

Originally Posted by zhajingjing

Hi,
I use mesh motion solver for a moving boundary, and it takes a lot of time to move the whole mesh, if setting the part of mesh just near the moving boundary to move can be realized(that means just solve mesh equation in a region near the moving boundary), then I can save much time to run the case.

So how to let the mesh motion solver just solve a small region near a moving boundary? Can someone give me a hint?
Thanks!

Jingjing

------------------------------------------------------------------------...

sunliming

Member

Posted in Uncategorized

Views 1272 Comments 0 sunliming is offline

Pop the hood on ANSYS meshing

Posted October 4, 2012 at 13:05 by PSYMN

Thought I would show a little about how to "pop the hood" on ANSYS Meshing and Access the ICEM Technology underneath...

Here is a link...

http://www.ansys-blog.com/2012/10/04...ive/#more-3335

PSYMN

Senior Member

Posted in Uncategorized

Views 3876 Comments 2 PSYMN is offline

Processor Affinity to Enhance Speed

Posted September 11, 2012 at 11:09 by Hisham (Notes for OpenFOAM!)
Updated September 12, 2012 at 10:02 by Hisham

To enhance the speed of running a solver one can use a "hard" assignment of the job to a specific core. This reduces the work needed to switch jobs between cores and enhances the speed. It is really neat if you need to do some other work on the workstation while the run is going on in the background.

Install:

Code:

# apt-get install schedtool

Use:

Code:

$ schedtool -a 5 10640

This command assigns job 10640...

Hisham

Senior Member

Posted in Uncategorized

Views 1786 Comments 0 Hisham is offline

under-relaxation factors -> level of residuals

Posted August 27, 2012 at 09:27 by kira

more helpful info on under-relaxation factors:

Quote:

Originally Posted by LuckyTran

No magic here, that's what's supposed to happen. Unless your solution is diverging, do not bother with the under-relaxation factors. If it is diverging, do as you did, lower the factors until you can a stable solution, and then raise them again if possible. If not, then it is a hint that there is an inherent stability issues in the problem you are trying to solve or perhaps one of your modeling parameters is incorrect.

All

...

kira

New Member

Posted in Uncategorized

Views 1675 Comments 0 kira is offline

what is under relaxation factor?

Posted August 27, 2012 at 09:23 by kira

something to keep in mind:

Quote:

Originally Posted by Phil
;140717

Each of the variables(mass,mom,density) represents an equation the solver is trying to solve. Each iteration the values obtained for the variables should get closer and closer together - converge. FOR SIMPLE PROBLEMS ESPECIALLY COLD FLOWS WITHOUT COMBUSTION YOU SHOULD SIMPLY KEEP THE RELAXATION FACTORS AT DEFAULT.

Sometimes for many many reasons the solution can become unstable so a relaxation factor is used - takes part of value from previous iteration

...

kira

New Member

Posted in Uncategorized

Views 2072 Comments 1 kira is offline