We would like to model the fall of an object from an airplane or helicopter, is it posible with FLUENT? (I am thinking in the possibilitie of moving mesh+FSI)

We need to study the aerodynamic of this problem and its impact with water..

Regards, Marcelo.

You will need to use the 6dof (degree of freedom) model inside FLUENT. The falling object is modelled as a rigid body, and the motion and updated positions will be calculated based on any aerodynamic or hydrodynamic loads from the CFD analysis. Obviously, this is a moving/dynamic mesh method, and some hefty UDFs are needed. Among others, you will need to identify the moment of inertia, mass, COG and other parameters with the UDFs.

Overall, the 6dof model is set up in the dynamic mesh section, goto Define>Dynamic Mesh. Please see in the FLUENT User's Guide about dynamic mesh panel, and also the UDF user's guide on the macros and scripting required for the UDF. If you have access to the FLUENT User website, you can also find an example of the 6dof UDF in there.

Hope that helps.