CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > Siemens

Scratch Space Error during combustion simulation

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   October 18, 2008, 04:40
Default Scratch Space Error during combustion simulation
  #1
Emmanuel Kasseris
Guest
 
Posts: n/a
Hello, I am running a simulation of (premixed) combustion in the cylinder of a gasoline engine.When combustion is turned off,the simulation works fine.With combustion on,however, it fails immediately after combustion begins with this message: *** Scratch unit 78, Failed to find scratch data CELL 1 56 1 1 *** Proc: 1 Error encountered, number: : 549

*** Error 549: Scratch/RAM file failed reading/writing

CELL 1 56 1 1

Most likely cause: full disk or not enough RAM memory

on the system.

If the problem persists contact User Support.

RUN STOPPED !!!

I have 8GB of RAM.Is the scratch space the tmpfs in Linux?How can I increase it? Any help would be much appreciated Thanks
  Reply With Quote

Old   October 18, 2008, 12:06
Default Re: Scratch Space Error during combustion simulati
  #2
azt
Guest
 
Posts: n/a
if you use bash then you can set the tmpdir

ie export TMPDIR='path to temp directory'
  Reply With Quote

Old   October 18, 2008, 15:55
Default Re: Scratch Space Error during combustion simulati
  #3
Emmanuel Kasseris
Guest
 
Posts: n/a
I did and it still fails with the same message.Could it be related to tmpfs and RAM instead of the tmp folder?or my setup? Thanks! Emmanuel
  Reply With Quote

Old   October 19, 2008, 04:43
Default Re: Scratch Space Error during combustion simulati
  #4
Balduin Bankerotti
Guest
 
Posts: n/a
Do you have a 64 bit version of linux and also the 64 bit version of star installed on your machine?

  Reply With Quote

Old   October 19, 2008, 07:41
Default Re: Scratch Space Error during combustion simulati
  #5
Emmanuel Kasseris
Guest
 
Posts: n/a
yes and may I add that this model works fine for cold flow.
  Reply With Quote

Old   October 19, 2008, 07:48
Default Re: Scratch Space Error during combustion simulati
  #6
Emmanuel Kasseris
Guest
 
Posts: n/a
Yesterday I tried setting TMPDIR=a dir with no limit for sure+adding 14 gigs of swap memory (default was 2G and my RAM is 8G) and I restarted the the calc from a couple of time steps before failing...... Still the same error! I am running it now restarting from 200 time steps before failing and monitoring RAM usage closely.It is using almost all of the RAM even before combustion starts...
  Reply With Quote

Old   October 19, 2008, 10:31
Default Re: Scratch Space Error during combustion simulati
  #7
usker
Guest
 
Posts: n/a
What is your grid size, and turbulence model you are using?
  Reply With Quote

Old   October 19, 2008, 11:40
Default Re: Scratch Space Error during combustion simulati
  #8
c.duckinson
Guest
 
Posts: n/a
did you follow the installation notes and set the swap space at least greater or equal than the RAM?
  Reply With Quote

Old   October 19, 2008, 16:22
Default Re: Scratch Space Error during combustion simulati
  #9
Emmanuel Kasseris
Guest
 
Posts: n/a
Initially the swap space was 2G (RAM is 8.2G).But I increased the swap space to 14G using a swap file and restarted the simulation.Same problem...I was actually monitoring RAM and swap space usage before and at the point it crushes (using the free command) and RAM usage was 8 out of 8.2G but swap space usage was only 48 Mb and didn't change as it was crushing, i.e. swap space use didn't suddenly increase...
  Reply With Quote

Old   October 19, 2008, 16:27
Default Re: Scratch Space Error during combustion simulati
  #10
Emmanuel Kasseris
Guest
 
Posts: n/a
around 700.000 cells.K-epsilon turb model with these values: TURBULENCE MODEL ............ => HIGH RE K-EPS MODEL |

| CONSTANTS ................. => C_mu=0.09, C_1=1.44, C_2=1.92, C_3=1.44, C_4=-0.33 |

| => cappa=0.419, Pr_k=1.00, Pr_eps=1.219, Pr=0.90
  Reply With Quote

Old   October 25, 2008, 18:12
Default Re: Scratch Space Error during combustion simulati
  #11
Emmanuel Kasseris
Guest
 
Posts: n/a
It turned out to be a bug in the CFM combustion model!!!!!!!!!! They are fixing it in a patch coming out next week!
  Reply With Quote

Reply


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
Scratch Space? B Bru Siemens 2 September 17, 2007 12:31
Max Scratch Space Ravi Siemens 2 May 18, 2007 02:54
Combustion space and glass flow modeling santosh Main CFD Forum 0 April 11, 2007 06:27
Fatal error error writing to tmp No space left on device maka OpenFOAM Installation 2 April 3, 2006 09:48
Large space simulation Yazhuo Qian Phoenics 2 March 27, 2003 12:13


All times are GMT -4. The time now is 11:58.