Controlling the Acoustic Resonance in a Corrugated Flow Pipe

A new experimental study, aimed at investigating the coupling between the flow in a corrugated pipe, the acoustically generated flow oscillations, and the emitted resulting noise is carried out. Hot-wire anemometry, Particle Image Velocimetry, and microphone measurements are associated to characterize the flow. The flow response to the corrugation is shown to fit to the sixth to ninth acoustic modes of the pipe according to the flow rate. When low frequency acoustically generated oscillations interfere with this, one checks that they either significantly reduce the noise level or modify the peak frequencies. In addition, theoretical/numerical works are also performed, in order to provide an analytical framework describing the acoustical properties of such corrugated pipe flows.