urgent! amplitude and frequency

Sheila

Hi! My name is sheila. I'm simulating unsteady vortex flow over circular cylinder. I want to variate the amplitude of sinusoidal movement. Does FLUENT automaticly generate sinusoidal function or I can define it externally? Is there any other way to variate the amplitude? Can somebody tell me about the vortex flow characteristics related to frequency and amplitude of vortex shedding variation? For example, when the frequency increases whether Cl also increases or decreases?

thank you very much I really appreciate your help