Hello,

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)

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.

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

hello,

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

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...

Hello!

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

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

I think in the GAMBIT Tutorial Guide the proplem that you are solving has been modelled. You can take help from there.

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 don´t 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.