CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > FLOW-3D

FLOW 3D version comparison

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

LinkBack Thread Tools Search this Thread Display Modes
Old   October 7, 2011, 14:35
Post FLOW 3D version comparison
New Member
Join Date: Oct 2011
Posts: 1
Rep Power: 0
sjv920 is on a distinguished road
Have recently gone back to comparing results obtained from different versions of the FLOW3D code we have on hand. We have discovered that there appears to be quite a bit of difference in the results produced when taking (all other inputs equal) a model in version 8.1 and running in 9.1 and later versions. Does anyone know of any major changes to the solver that would produce these discrepancies?
The problem involves an outflow of fluid from a tank. In version 8.1, there is a lot of sloshing at the free surface as the tank is drained, where in 9.1 and later versions, the free surface remains relatively flat. There are some forces put on the tank in the non-inertial reference frame model, which should result in some free surface movement, however the simulated differences are on an order of 10 times greater in magnitude in 8.1 compared to 9.1. First order momentum advection is used in all simulations, along with a SOR pressure solver, a laminar, viscous flow, and a non-inertial reference frame specified by a movin.inp file.
I know 8.1 is an old version of the code, however I would think that a simple moving, draining tank should be easy enough to model such that results should be similar no matter which version is used. Therefore, it is a little discouraging to see such a difference and tough to justify which version simulates the model more “realistically” without a better understanding of what changes may have been made to the solver to produce these differences.
sjv920 is offline   Reply With Quote

Old   October 21, 2011, 15:50
Senior Member
Jeff Burnham
Join Date: Apr 2010
Posts: 204
Rep Power: 17
JBurnham is on a distinguished road
Sam - you should have already been contacted by Flow Science about this. In short, there were models and new inputs added since 8.1 that require more input flags. This especially creates differences when the same prepin file is used for both runs (8.1 and 9.3).

Two major changes affected the viscous flow model and the GMRES pressure solver. The latter did not exist in 8.1 and became the default in 9.3. The viscous flow model requires activation flag in 9.1 which is off by default, while in 8.1 viscous flow option was activated if a positive viscosity coefficient was provided. There were two major releases in between – 8.2 and 9.0, so a bunch of other fixes could have been made in those releases too.
JBurnham is offline   Reply With Quote


flow 3d, sloshing

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Flow meter Design CD adapco Group Marketing Siemens 3 June 21, 2011 08:33
OpenFOAM-1.6 install cookbook MadsR OpenFOAM Installation 372 November 20, 2010 11:57
paraFoam reader for OpenFOAM 1.6 smart OpenFOAM Installation 13 November 16, 2009 21:41
Mass flow and U-Mom flow in CFX Zhihua Xie CFX 0 September 3, 2007 09:49
transform navier-stokes eq. to euler-eq. pxyz Main CFD Forum 37 July 7, 2006 08:42

All times are GMT -4. The time now is 17:53.