Flow-sound interaction mechanism of a single spirally finned cylinder in cross-flow

Over the years, some effort has been expended in the improvement of heat transfer performance in tubular heat exchangers. This can be achieved by adding different types of fins to the outer tube surface, effectively increasing convective heat transfer. However, the addition of fins may lead to the generation of severe noise, caused by the coupling between the vortex shedding frequency and one of the acoustic cross-modes of the duct housing the finned tubes. This may reduce the service life of the heat exchangers, and adversely affect the health of individuals working in the proximity of such noise. Since the flow-acoustic phenomenon of finned tubes are not well understood, it can be dangerously unpredictable. Therefore in this thesis, the flow-sound interaction mechanism of a single spirally finned cylinder in cross-flow is investigated. Moreover, a simple noise control technique is proposed to suppress the onset of acoustic resonance excitation