Visualization of acoustic scattering by elastic cylinders at low <i>k</i> <i>a</i>

Abstract

Theoretical studies have shown the great importance of circumferential waves in acoustic scattering by infinite elastic cylinders immersed in a fluid. The ‘‘Resonance Isolation and Identification Method’’ (RIIM) has allowed us to separate the resonances produced by circumferential standing waves by recording the free vibrations which are still present for some frequencies after the forced excitation has stopped. In this paper, the problem of acoustic scattering is studied by a stroboscopic Schlieren visualization method at low frequencies (0&amp;lt;ka&amp;lt;30). We attempt to establish that the acoustic beams generated in specific directions, when the cylinder is no longer excited, are actually issuing from the standing wave antinodes.