How to simulate piston motion in simple cylindrical geometry
 

I am beginner..please please help me

I have simple cylinder in design modular
Specifications:-
1. Diameter=50mm
2. Height=120mm
With named 3 selection as
1. TOP for cylinder head
2. Wall for side wall
3. Piton
The question piston to move with z=55mmsin(100t) where t is time z=0 is the center of the cylinder with axis in z direction.

How will i do this?? I don't know coding of fluent. Please help me..