boundary conditions : water vortex flow through a cylinder
 

I'm new to Ansys and I'm trying to simulate flow of water through a cylindrical basin with a large inlet hole and a small exit hole as shown in the figure(see the link). How should I go about defining boundary conditions for the problem and what models should I use in Ansys Fluent? Please help!! (How should I approach the problem?)

Image link :
http://www.google.com.np/imgres?imgu...ed=0CEkQrQMwDw