Phase-Locked PIV Measurements of Vortex Shedding Characteristics Downstream of Straight Circular Finned Cylinders During Acoustic Resonance

Abstract

Excitation of acoustic resonance by flow perturbation downstream of cylinders can result in hazardous levels of acoustic pressure. Previous studies have shown that straight finned cylinders are susceptible to flow-excited acoustic resonance. In this work, the excitation of acoustic resonance by flow around finned cylinders of different fin parameters including the spacing between the fins, the thickness of the fin, and the height of the fin is investigated. All the investigated finned cylinders have the same equivalent diameter. Phase-locked particle image velocimetry (PIV) measurements are carried out during acoustic resonance to characterize the flow field downstream of the cylinders and identify the influence of the fins on the flow structures at the peak of resonance excitation. Results show that straight circular fins excite acoustic resonance at lower velocities and result in higher sound pressure level compared with a single bare cylinder of the same effective diameter. This behaviour is due to the effect of fin parameters on the strength and the formation length of vortices shed during the acoustic cycle. A brief summary of the results is presented in this paper.