Sound scattering by localized vortices in the wake of a flat plate

LEAF-NL, Departamento de Ingeniería Mecánica, Universidad de Chile - Casilla 2777, Santiago, Chile

^a rohernan@ing.uchile.cl

Received: 17 September 2011
Accepted: 30 November 2011

Abstract

We report an experimental study of the impulse response of the wake of a thin flat plate using a moving flap at the trailing edge as a source of local perturbations into the wake. We characterize the spatial and temporal properties of the wake disturbances by means of hot-wire anemometry and sound scattering by vorticity fluctuations. An important result is that the characteristic wavelength of the wake disturbance during the impulse response remains independent of the mainstream flow velocity because it is the inertial resonant mode found in Hernández R. H. and León M., EPL, 90 (2010) 24001 and Hernández R. H. and Vial M., EPL, 81 (2008) 64007, which is triggered during the impulse response of the wake.