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Gaylor April 2, 2007 07:54

Modelling a sail boat on FLUENT

We are trying to modelize a sail boat on Fluent. At the moment, we are using the VOF model (air/water). But we have problem with the boundary conditions. We don't find the right parameters.

Our parameters for the moment: Segregated, Unsteady, k-epsilon, 2 inlets (air/water), 2 outflows.

We don't manage to converge with two Velocity inlets (one for the air and one for water) with this model and how could we do this with fluent?

Is the Open Channel Flow well appropriated for this kind of problem?

Thank you for your help (in french or english)

Charles April 2, 2007 15:48

Re: Modelling a sail boat on FLUENT
You shouldn't need 2 inflows & 2 outflows. In Fluent 6.2.16 and onwards, the easy way of doing this is by specifying Open Channel boundaries. The outflow has to be a pressure boundary, I think. Grid quality is vital, otherwise the calculation will blow up early, and you also have to be ultra-conservative on relaxation values for the start up. And the whole thing takes a loooong time.

Gaylor April 3, 2007 02:30

Re: Modelling a sail boat on FLUENT
Hello Charles, thank you for your answer.

We have one more question concerning the open channel boundary conditions: do you think the inlet has to be pressure too?

thank you

H.A.S April 3, 2007 03:40

Re: Modelling a sail boat on FLUENT

this was already done on the documentation of the fluent (the newest version) , uu cancheck with it ; regards

Gaylor April 3, 2007 03:40

Re: Modelling a sail boat on FLUENT
Our boat is a single-hulled vessel with one keel, two rudder blade.

It is a 12 meters long boat used for competition.

For the moment we are working in a cylindrical environment and we still wonder if it is a better solution than working in a simple rectangular environment...

Gaylor April 3, 2007 04:54

Re: Modelling a sail boat on FLUENT

We have already this documentation for Gambit but we did not find it for Fluent. If you have the link for the documentation on fluent it would be kind from you to give me.

Thank you

H.A.S April 3, 2007 06:08

Re: Modelling a sail boat on FLUENT
sorry i didnt find it for fluent !! u know i checked the gambit documenattion aand my answer was based of the gambit ;

regards, H.A.S

Pradeep April 8, 2007 20:40

Re: Modelling a sail boat on FLUENT
I think in the GAMBIT Tutorial Guide the proplem that you are solving has been modelled. You can take help from there.

santi April 27, 2007 04:55

Re: Modelling a sail boat on FLUENT
Velocity inlet for the air and for water. Pressure outlet for the outflow. Patch he flow with the speed of the velocity inlet, if you donīt do this a wave will appear. This can give problems of convergence.

If you need help send me a message. I am doing something similar.

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