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-   -   VOF WAVE/ DFBI (http://www.cfd-online.com/Forums/cd-adapco/56875-vof-wave-dfbi.html)

MAB November 13, 2008 08:17

VOF WAVE/ DFBI
 
is it possible to use VOF wave for a non moving body in the domain. ??

ping November 13, 2008 10:12

Re: VOF WAVE/ DFBI
 
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.

MAB November 15, 2008 14:12

Re: VOF WAVE/ DFBI
 
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.

ping November 15, 2008 22:32

Re: VOF WAVE/ DFBI
 
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


MAB November 16, 2008 18:36

Re: VOF WAVE/ DFBI
 
Thanks .... Could you please tell which package is been used for meshing of the demo boat.

ping November 16, 2008 20:03

Re: VOF WAVE/ DFBI
 
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.

MAB November 17, 2008 06:22

Re: VOF WAVE/ DFBI
 
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.


ping November 17, 2008 22:34

Re: VOF WAVE/ DFBI
 
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.


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