MANUAL Fluent 5

Volume of Fluid : Free Surface Flow

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For a good start with VOF model, you have to be sure water and air are present and well defined in yout materiall database. Then you have to define a laminar, graviational and unsteady flow using the standard way.

To use a VOF model, chose it in Define -> Models -> Multiphase

It's important to keep water-liquid in the first phase and air in the second. The use of a VOF model implies a particular numerical algorythm PISO :

Define it : Solve -> Controls. It's also recomanded to set all the relaxation factors to 1 but be aware of the explosion of the code....

This is necessary to use VOF model but you will surely be able to initialize the different region of your computational domain. For that use : Adapt -> Region

Select your coordinates linked to the kind of shape you want to use and select Adapt. This will refine the mesh on the zone you chose. Then select Mark to give a name to this section. You can check if the section is well defined using Manage. if you have well followed these few instructions you must see one or several zones called hexahedron-r?.

You can now initialise your solution giving a value to air volume fraction ( 1: air , 0: water ) and after that, patch the zone you decide with the same technique selecting it in the frame: Registers to patch.

If all has been well done, you can now iterate and enjoy ......