Tailoring the Waveform of a Periodic Flow With a Programmable Damper

Abstract

Investigators of unsteady flows normally have little control over the waveform of the flow unsteadiness. This paper describes a programmable rotating blade damper system that is capable of producing a near sinusoidal velocity waveform without wind tunnel resonance. By varying the angular velocity of the rotating blades in a damper at various times in a cycle the desired waveform can be obtained. The amplitude and frequency of the flow oscillation are also adjustable. There is little variation of the period of the waveform and the results are highly repeatable.