CFD Online Logo CFD Online URL
Home > Forums > FLUENT

ATTENTION!! Validty of Fluent's VOF??

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

LinkBack Thread Tools Display Modes
Old   February 16, 2004, 10:22
Default ATTENTION!! Validty of Fluent's VOF??
Posts: n/a
Hi all,

I am simulating free falling water drops (d=1-4 mm) in a surrounding media of supercritical CO2 (liquid like density, gas like viscosity). The terminal velocities I got so far are about 50 % lower than I expected. Moreover, the solution is highly dependent on the time step (an increase in the time step may result unpysical deformation, even the solution seems to converge!!) In addition, simulation is unstable for smaller drops, i.e. when the drop is 1mm, some strange velocity currents appear in the drop, which is not the case for bigger drops. (for all simulations diameter is resolved by 80 cells in 2D DP solver, time step btw. 10^-4 - 10^-5 s, geo-recon. scheme used, no turbulance model was employed)

After reading the article of C.W. Hirt (the founder of VOF) in , I have a doubt that Fluent is able to make precise VOF calculations. He does not even call them (VOF in some commercial CFD codes, icluding Fluent) as VOF, but pseudo-VOF instead!!

What are the experience of the VOF users, regarding to validation of the simulation results?

One more thing. I think the following page gives a good summary of basic CFD concepts, which may be helpful for the CFD beginners (but it is so much filled up with the promotion of their Flow3D software):
  Reply With Quote

Old   February 18, 2004, 12:59
Default Re: ATTENTION!! Validty of Fluent's VOF??
Posts: n/a

I had good expirience using VOF (fluent version 6.1, the version before did't work well) for dam break simulation, big drop falling into water... Problems occured with rising bubble where the solution was not phisical.

Best regards

  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
Question:Considerations about the evaporation in VOF dokeun FLUENT 10 February 24, 2011 21:47
2 different time steps in Fluent's VOF?? thecfduser FLUENT 7 March 17, 2010 18:59
ATTENTION!! Validty of Fluent's VOF?? ozgur Main CFD Forum 3 February 18, 2004 19:19
Difficult BCs about Freesurface Simulation by VOF Yongguang Cheng FLUENT 0 September 19, 2003 07:39
Moving mesh or VOF? Giovanni Main CFD Forum 16 September 24, 2001 08:25

All times are GMT -4. The time now is 17:47.