Effect of Sound on Vortex-shedding from a Circular Cylinder : Acoustical Vibrations Directed Normal to the Axis of Cylinder

Abstract

An experimental investigation has been carried out to study the acoustic interferences in vortex-shedding from a circular cylinder in a crossflow subjected to the acoustical vibrations whose direction is normal to the axis of the cylinder, and in particular, to search for the correlation of vortex-shedding along its axis. The results indicate that the effects of the acoustical vibrations whose direction is normal to the axis of the cylinder are similar to that of the acoustical vibrations directed along its axis on the vortex-shedding from the cylinder, and both vibrations increase the spanwise correlation of the cylinder wake. The acoustic frequency which produces powerful effects on vortex-shedding corresponds to the frequency of laminar-turbulent transition wave in a separated shear layer, and there are critical sound pressure levels in these acoustical vibrations.