CFD Online Discussion Forums

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-   -   VOF Damping (http://www.cfd-online.com/Forums/star-ccm/99992-vof-damping.html)

lava12005 April 17, 2012 23:54

VOF Damping
 
Hi, I am wondering about how to use damping in free surface flow.
I am simulating a towing tank test of a planing type hull of length ~1m
I put my boundary 2L upstream, 6L downstream, 3L on the transverse direction.

I am running calm water condition, and would like to know what is the significant of wave damping, and in Star-CCM+ is there any guidelines on how do we 'select' the appropriate wave damping length?

Thanks

ryancoe April 18, 2012 10:33

Are you asking about boundary conditions used to damp wave reflections?

lava12005 April 18, 2012 11:11

No, I am want to know how far should we apply the damping from the field of interest, and also how do we decide the VOF wave damping length

And also does damping is also important if we are running Flat Wave model?

arun7328 June 14, 2013 09:23

Hi,

I also have a question regarding wave damping. Is there a way to increase the damping coefficient? Looks like I have some wave reflection happening. I saw the manual says it damps the w velocity. Should my vertical then be in z direction? My vertical is y axis. Just wanted to make sure.

need guidance if you know
Regards
Arun

Higuel December 1, 2014 11:57

What CD-Adaco says
 
Hello all,

I have the same difficulty in selecting the wave damping length for my resistance simulations.

It is said in the Steve Portal Article Number 5216, that "the VofDampingLength to be at least of the order of the ship length". However, the EHP resistance assistant makes this length twice the ship length.

I have never had the opportunity to compare the results by using L or 2L. Does anyone?

Cheers,
Higuel

lava12005 December 1, 2014 21:16

Yes, twice the ship length is still in order of the ship length (:p)
You can try to compare I suggest and see the difference..


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