CFD Online Logo CFD Online URL
Home > Forums > STAR-CCM+

VOF wave getting damped.

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

LinkBack Thread Tools Display Modes
Old   September 11, 2013, 07:07
Default VOF wave getting damped.
Arun Krishnan.L.H
Join Date: Jan 2013
Posts: 75
Rep Power: 4
arun7328 is on a distinguished road
Dear All,

I am going to work on wave interaction on ships and the dynamic forces for various cases. Just to get the modelling and meshing right for VOF wave and to what comes out of the software for a user defined wave, I am simulating first order waves in a rectangular domain.

The domain is 75m(x), 10m(y which is the direction of wave height), 1m(z direction). The free surface is initialized so that the domain is equally divided. The coordinate of y axis of free surface is 0.

I have defined a wave of length 5 mts, current/wind velocity 1.5 m/s, amp 0.1 mts. The mesh sizes on the free surface is refined using a block of height 0.3 m. The x and z refinement are wavelength/80 and y axis is amp/20. Time step is wave period (2.4*80). I have run the simulation using 50 and 70 inner iterations but the nature of the pressure plot seems to be that of a damped oscillation. Though the waves are not becoming completely flat , which was an issue i had before, it gets damped a little. The point on water level of the wave is 0,0,0. The distance from the wave to outlet is 50mts.

I have also changed the VOF relaxation from 0.9 to 0.5 but there is no change. Can anyone please guide me regarding what is going wrong or what other parameter i could change. I am running unsteady, inviscid model and 1st order solver.

Attached Images
File Type: jpg vof initial.jpg (9.5 KB, 64 views)
File Type: jpg vof after 4 sec.jpg (10.3 KB, 61 views)
arun7328 is offline   Reply With Quote

Old   December 18, 2013, 09:34
New Member
saeed barzegar
Join Date: Feb 2012
Posts: 2
Rep Power: 0
saeed.barzegar.v is on a distinguished road
Dear Arun

I had a same problem. I suppose, you are working on old version of fluent? if it is true, you can follow another simple way (by new version of fluent (in ANSYS 13 or 13))
in ANSYS13-fluent, there are options for modeling wave (Airy, stocks,...) and free surface, but it takes times to realize. however, in this way you can simulate completely your problem.
my firs your problem was like "picture 1111" (likes your problem) and my result after modeling in new version of fluent is like "picture 2222" (that wave does not damp)

Also this link can help you for modeling wave in ansys-fluent: step by step for VOF modeling

I hope my suggestion will be helpful.
Attached Images
File Type: jpg 1111.jpg (38.6 KB, 49 views)
File Type: png 2222.png (3.8 KB, 43 views)
saeed.barzegar.v is offline   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
vof method of wave height gtfeng STAR-CCM+ 2 June 8, 2013 02:32
VOF wave hydraulic STAR-CCM+ 4 August 16, 2012 11:55
5th Order VOF Wave miharbi STAR-CCM+ 3 May 2, 2012 05:51
VOF wave ymz_0308 STAR-CCM+ 0 October 24, 2011 23:26
HELP! UDF sinusoidal wave, VOF model, porous face! A8anato_psofimi FLUENT 2 November 10, 2009 15:42

All times are GMT -4. The time now is 17:37.