How to define Dynamic Mesh boundary condition?

David

I want to simulate a FSI problem like wind acting on a flexible structure using loose coupling method based on the Fluent and structure analysis software .The dynamic mesh model was employed in Fluent to calculate the pressure. In each time step, it needed to define the velocity on the dynamic boudaries, which calculated from the CSD on the discrete nodes. My problems are:

1. I don't know how to define this dynamic boundary. Using UDF or Profile?and How? Could you illustrate me a example?

2.How to determine the time step to avoid the oscillation during the calculation?

Any suggestion would be great appreciated.David