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

VOF WAVE/ DFBI

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 13, 2008, 07:17
Default VOF WAVE/ DFBI
  #1
MAB
Guest
 
Posts: n/a
is it possible to use VOF wave for a non moving body in the domain. ??
  Reply With Quote

Old   November 13, 2008, 09:12
Default Re: VOF WAVE/ DFBI
  #2
ping
Guest
 
Posts: n/a
yes - you simply keep the body locked in all six degrees of freedom. You can even remove the 6DOF model after setting the wave up. NB v306 has 3 wave types: 'flat', 1st and 5th order Stokes.
  Reply With Quote

Old   November 15, 2008, 13:12
Default Re: VOF WAVE/ DFBI
  #3
MAB
Guest
 
Posts: n/a
I tried it. deleting 6DOF doesn't work (ERROR of no rigid body pops up). Initial conditions looks fine . but when i run the simulation , wave's shape changes and it ends up with error.
  Reply With Quote

Old   November 15, 2008, 21:32
Default Re: VOF WAVE/ DFBI
  #4
ping
Guest
 
Posts: n/a
Before I submitted the post I tested that in v304, so I'm not sure what else you have not set up correctly. Try leaving 6DOF enabled, but just don't free up any of the degrees - I have run several models like this. If this does not work there is something else incorrect in your setup - watch the DBFI video demo video again.

Here is a quick check list to set a case up from scratch after meshing:

Physics 6 DOF Multi Phase Mixture (ie VOF) Implicity unstready Gravity etc as required

In Eulerian Multiphase

Water phase - add and define

Air phase - add and define

6DOF do 6 DOF bodies properties (mass, MoI, init. vel etc) which DOF are to be freed (can be none of course) ? want a new CSYS - not essential

Do Wave setup in Tools as required

Set initial conditions: Static Pr = FF Hydrostatic pressure of wave 0 Vel = vector FF = Vel of wave 0 Vol Frac = composite - Water = Vol fract of heavy fluid,

Air = Vol fract of light fluid Gravity in correct direction ?

BCs Inlet

vel to components, vector FF = Vel of wave 0

vol fract - as per initial conditions copy and paste these settings to other walls (sides, top, bottom) - very important! Outlet to Pressure with FF Hydrostatic pressure of wave 0

Solver time step to .01 inner iters = 5 max time = ??

Reports & plots - translation, angle etc

  Reply With Quote

Old   November 16, 2008, 17:36
Default Re: VOF WAVE/ DFBI
  #5
MAB
Guest
 
Posts: n/a
Thanks .... Could you please tell which package is been used for meshing of the demo boat.
  Reply With Quote

Old   November 16, 2008, 19:03
Default Re: VOF WAVE/ DFBI
  #6
ping
Guest
 
Posts: n/a
STAR-CCM+ is very suited to meshing this form of marine case now that anisotropic trimmed meshing has been added (previously I used pro-am) to create a finer mesh at the expected water surface in the up-down direction, while maintaining a larger size horizontally.
  Reply With Quote

Old   November 17, 2008, 05:22
Default Re: VOF WAVE/ DFBI
  #7
MAB
Guest
 
Posts: n/a
Thanks again. How i can go for such meshing options while selecting mesh models in starccm. Is there any tutorial for this type of meshing. thanks in advance.

  Reply With Quote

Old   November 17, 2008, 21:34
Default Re: VOF WAVE/ DFBI
  #8
ping
Guest
 
Posts: n/a
I suggest doing all the meshing tutorials (tutorials 2) including the trimmer mesh one. Then read about volume source in the help here:

Using Tools > Working with Volume Shapes > What Are Volume Shapes?

and add one to the trimmer mesh from above as a trial.
  Reply With Quote

Reply

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
Info on DFBI for Ship Motion Simone Siemens 17 March 29, 2016 21:19
i need info on DFBI Eleazar Siemens 7 September 2, 2010 03:13
DFBI, turbulence model and ship motion ettax Siemens 1 June 4, 2010 12:31
DFBI question Atlas Siemens 3 January 21, 2009 16:21
VOF WAVE/ DFBI MAB FLOW-3D 2 November 14, 2008 00:02


All times are GMT -4. The time now is 02:31.