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

Transient Flow, Transient Pressure in Work Bench

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 4, 2007, 11:11
Default Transient Flow, Transient Pressure in Work Bench
  #1
Erich
Guest
 
Posts: n/a
Hello,

We are modeling a rotating fan that undergoes relatively large changes in pressure as it rotates. In order to get the mapping to work in the same global coordinate system in Workbench, I rotate the stationary components in Pre and set up definition files for multiple time steps/angle of rotations. When each pressure is applied at successive time steps, the Resultant loads map at 100% and appear correct. The only problem is that the stress levels gradually increase to a much higher value than predicted in the static analysis. The overall magnitude of the pressures individually would not yield such a high stress. It is as if the pressures are additive, as opposed to only applied at those time steps. Is there a CMD file in Workbench that would ensure the CFX pressures are only applied at their own individual time steps? Could there be something else?

Thanks for your help,

Erich
  Reply With Quote

Old   May 8, 2007, 12:55
Default Re: Transient Flow, Transient Pressure in Work Ben
  #2
Erich
Guest
 
Posts: n/a
Update:

Our Ansys Support office gave us a work around. There are Ansys commands available to turn on and off the pressure loads at their respective time steps. Otherwise, the pressures are seen as additive...

Thanks Ansys Support!

Erich
  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
simple model, difficult outlet Eric CFX 7 May 23, 2014 09:13
UDF for transient pressure inlet, mass flow check at nozzle exit and volumetric heat kokoory FLUENT 0 August 17, 2011 03:07
what the result is negatif pressure at inlet chong chee nan FLUENT 0 December 29, 2001 06:13
fluid flow fundas ram Main CFD Forum 5 June 17, 2000 22:31
Hydrostatic pressure in 2-phase flow modeling (long) DS & HB Main CFD Forum 0 January 8, 2000 16:00


All times are GMT -4. The time now is 04:38.