basics for unsteady simulation

ernani

hello, I'm going to run my first 3D unsteady simulation with fluent and I have some doubts with settings.. Usually I simulate wing profile, but this case is a rectangular chamber whit slot cut along over side and pulsed pressure imposed through connection tube (circular) at the bottom side, I'd like to know:

1) which is the more suitable turbulence model for this kind of situation (for steady simulation for profile usually I use SA..)

2)I'm interested to study the phase and amplitude difference between input pressure and exit slot pressure, so how much importance I should take for meshing (I do not care about boundary layer on wall for example, but is same important to have right refinement on wall?)

3)When I perform unsteady simulation is important to start from a steady solution or I can run directly with used defined function with unsteady pressure?

any other advace for unsteady settings is very appreciated.. bye