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

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