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 Sundar Prasad February 9, 1999 22:34

Free Surface Flows / Ocean Waves / Far-field boundary conditions

What is the opinion of commercial CFD users out there on the free surface modeling capabilities of the codes they are using? Is FLOW3D still the obvious choice or are there other tools now which have improved upon the capabilities of FLOW3D?

I am looking for a robust code which will allow me to model the interaction of ocean waves with structures in the flow field. A VOF code such as FLOW3D seems to be a good candidate since it can handle free surface break-up. Do any other products offer similar features?

In addition, what would be the easiest method to absorb wave energy in the computational domain? I don't think that commercial codes have radiation boundary conditions (or wavemaking boundaries for that matter) for allowing wave energy to freely exit. Would some form of free surface damping work?

Regards,

 Yong-Bum Lim February 22, 1999 14:54

Re: Free Surface Flows / Ocean Waves / Far-field boundary conditions

In addition, what would be the easiest method to absorb wave energy in the computational domain? I don't think that commercial codes have radiation boundary conditions (or wavemaking boundaries for that matter) for allowing wave energy to freely exit. Would some form of free surface damping work?

In physical phenomena, pressure disturbance caused by the interaction with structure is much smaller than the pressure of acean waves(depends on the wave amplitude though). I used to simulate the interaction between ship which is advancing to Stokes 2nd waves. The biggest problem I faced at the moment was how to deal with outflow boundary conditions. I tried 2nd order Neumann condition, but it didn't work properly. It also reflected the wave at downstream, because the wave potential of high amplitude wave was so dominant. The last choice I tried was damping zone. It is actually pretty easy, u(v,w and p) = DAMP * u(v,w and p) DAMP = -0.5 * {(X - X_out)/(X_dout - X_out)

where (X_dout - X-out) : length of damping zone

(X - X_out) : length from downstream If you use this damping function, you may have to apply pretty long damping zone with course grid.

Hope it will hep you out.

Best wishes, Yong

 bae jun ho March 10, 1999 07:47

Re: Free Surface Flows / Ocean Waves / Far-field boundary conditions

dear youg-bum my name is jun ho Bae I live in Republic of Korea If it's possible, I want you to give me some information I saw the journal : " VOF method for the Dynamics of free boundary" by C.W.Hirt but I don't know how I contact Los Alamos Scientific Laboratory in which the jouranl was sended If you know, Please contact to me.... such as home page and if you want some information for free surface, call me. sincerely.

pf) My professor name is Jae Min Hyun

 Swungho Lee April 9, 1999 04:44

Re: Free Surface Flows / Ocean Waves / Far-field boundary conditions

Hi, Mr. Bae

I am working on free surface flow. So, we can discuss about that. Please, call me. (Tel. 052-230-5544)

Swungho Lee

 Dr. V.Batischev April 25, 1999 23:48

Re: Free Surface Flows / Ocean Waves / Far-field boundary conditions

My scientific interest are thermocapillary fluid flow in thin viscous layers, self-similar solutions of Navier-Stockes equations for fluid flow with free surface, bifurcation regimes of fluid flow with free surface.

I seek scientific contacts in problems of fluid flow with free surface. 26 April 1999 Dr. V.Batischev. Rostov State University. Russia.

 Vivich Silapasoonthorn May 4, 1999 10:25

Re: Free Surface Flows / Ocean Waves / Far-field boundary conditions

Dear all engineers, I am working with free surface on liquid fuel as a project at university. If you have any information about this subject, which may be useful for my project. please let me know. thank you so much. Vivich S.

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