I´m trying to model a sail in 3D flow. Can I generate an open shell instead of a solid?

Yes you can. Create your volume. Then import or create the surface of your sail. Then split the volume with the surface. Now you have a volume with a surface cut within the volume. Then, when defining your bc's you define this as a wall. When you import it into Fluent, Fluent will create a "shadow zone". Don't worry about it. Walls are single sided bc's, so the "shadow zone" is just the other side of the wall. The only downfall is that this is a single surface, so you will have the same mesh on the positive and negative side of the sail surface. You could split the volume in half, with the sail being one of the surfaces used to split the volume. When you're splitting the volume, use the connect option turned on for all of the surface splits EXCEPT for the surface of the sail. Now you'll have two volumes that share all of the faces except that of the sail. Now you have a positive side and a negative side to the sail, and these can have different meshes. Define both as wall conditions. Fluent will not create the "shadow zone" if you use this technique.

Hope this helps, and good luck, Jason

Thank You very much for your detailed guidelines. I`ll start trying this way right now.

Thanks again.

Thank You very much for your detailed guidelines. I`ll start trying this way right now.

Thanks again.