Control of Vortex Shedding and Acoustic Resonance of a Circular Cylinder in Cross-Flow

Abstract

Abstract This paper presents an experimental study of the aeroacoustics response from a circular cylinder in cross-flow with a control rod. The effectiveness of the control rod on suppressing acoustic resonance excitation is investigated. The control rod diameter-to-circular cylinder diameter ratio (d/D) is fixed at 0.21. The gap (G) between the circular cylinder and the control rod is taken at 0.11D. The rod is placed at several angular positions, which varied from 0° (front stagnation of the main cylinder) to 180° (base of the main cylinder). Phase-locked particle image velocimetry (PIV) measurements are performed during acoustic resonance to visualize the coherent vortex structures downstream of the cylinders. The results show that the placement of the control rod significantly influences the Strouhal periodicity with great dependence on the rod’s angular orientation. Moreover, at some angular positions, the existence of the rod has resulted in a reduction of the sound pressure level (SPL) generated during acoustic resonance excitation. However, at other angular positions, the rod has resulted in a stronger resonance excitation. This behavior is due to the profound effect of the control rod’s angular position on the formation of vortex cores during acoustic resonance. A brief summary of the results is presented herein.