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Old   March 23, 2005, 13:28
Default memory problem
  #1
wilson
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Hi CFX users I am doing a project on Hydrofoil of a submarine the dimensions of the Hydrofoil is up to the scale 1:1 . Now I have to find out the cavitation occurring due to flow of water. The project is similar to the tutorial on Hydrofoil. I am giving boundary condition values just as given in the tutorial. But I am facing a very unusual problem.

ERROR #001100279 has occurred in subroutine ErrAction. | | Message: | | *** Run-time memory configuration error *** | | Not enough free memory is currently available on the system. | | Could not allocate requested memory - exiting!

This is the message that I receive in the out file generated. I made sure that ample memory is available in the hard disk but still the problem remains the same. In my hard disk free space left is 2 GB. RAM size is 1 GB. Is more space required than this or the problem lies somewhere else. Can any of u guys help me out?

Regards wilson

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Old   March 23, 2005, 14:35
Default Re: memory problem
  #2
caty
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I don't think that the message reffers at the space avaliable on the disc, but to the RAM. 1GB may not be enough is you have a very fine mesh. This is what happend to me as well.

There is here somewhere on the forum a post that says how to calculate the Ram required by a certain number of nodes.
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Old   March 23, 2005, 16:24
Default Re: memory problem
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Akin
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I think the ratio from my experience is about 0.55 using tet and wedge elements, that is you will need 550mb to solve 1 milliion volume mesh. However, I also found out that it depends on the solution strategy as well. Finally, I like running on Linux machines, I get about 1.8Gb of ram out of 2 on each computer in the cluster, when I use WinXP its about 1.5-1.6Gb and sometimes less. Try running in Parallel, of course this are my experiences, some one may feel differently.
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Old   March 23, 2005, 17:35
Default Re: memory problem
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Glenn Horrocks
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Hi,

CFX is a node centred solver, not an element centred solver so it is more meaningful to use the number of nodes rather than elements.

In my experience I can run about 1 million nodes in two seperate 1GB partitions on a dual processor Xeon/WinXP machine for a single phase compressible simulation. Obviously things like multiphase will reduce that as more variables are stored per node. I would guess with 1GB ram you could run about 400k nodes.

As Akin says, I suspect you will need to go parallel to get a realistic simulation size.

Glenn Horrocks
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Old   March 24, 2005, 06:47
Default Re: memory problem
  #5
wilson
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thanks all of u guys. its working!! i appreciate your help.

regards wilson
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Old   March 30, 2005, 07:36
Default Re: memory problem
  #6
wilsondeo
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guys i am now facing new problem in the same cavitation problem. after 10 iterations i get a message of fatal error and the solver stops. i managed to get the number of nodes within limit. can't figure out why this fatal error comes. anyone have faced this problem before.

regards wilson
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Old   March 30, 2005, 18:34
Default Re: memory problem
  #7
Glenn Horrocks
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Hi,

If the simulation solves for a while then crashes then you have diverged the solver. Have a look in the documentation regarding tips for obtaining convergence.

Glenn Horrocks
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