CFD Online Logo CFD Online URL
Home > Forums > Siemens

DISS causes simulation to diverge

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

LinkBack Thread Tools Display Modes
Old   October 21, 2005, 05:27
Default DISS causes simulation to diverge
Posts: n/a
Hello everyone

I am trying to run an unsteady flow in a simple volume - an inlet pipe and an outlet pipe connected to the same face of a cubic volume. I am using a pressure pulse as defined in a .dat file as my pressure inlet, and outlet pressure is constant at zero.

I know the boundary conditions are ok, because I have 3 different variations of my simple simulation and the first two converge easily. However, this simulation diverges at timestep 1 with DISS at 5.51E+17 and ENTH at 2.95E+05. All other residuals are 0.00E+00

When I run it as laminar it diverges at timestep 2, but the residuals are all 0 so I don't know what causes it.

Does anyone have any ideas?
  Reply With Quote

Old   October 21, 2005, 05:45
Default Re: DISS causes simulation to diverge
Posts: n/a
try reducing the pressure under relaxation factor. say 0.8. default is 1. check whether PISO correctors are reaching to its limit and courant number (normally 100).
  Reply With Quote


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
TurbFoam diverge ivanyao OpenFOAM Running, Solving & CFD 6 January 11, 2009 08:41
diverge with low Re numbers hui Main CFD Forum 2 April 10, 2007 07:16
2D case, diverge beginner Main CFD Forum 0 April 6, 2005 09:35
Converge and diverge Jack Main CFD Forum 4 February 24, 2002 23:43
Particles=>gen/diss of tur in cont phase david FLUENT 0 January 18, 2002 00:09

All times are GMT -4. The time now is 17:00.