18/09/2014 Physics
DOI: 10.1155/2014/392138 SemanticScholar ID: 55599698 MAG: 2086433080

Sound Scattering and Its Reduction by a Janus Sphere Type

Publication Summary

Sound scattering by a Janus sphere type is considered. The sphere has two surface zones: a soft surface of zero acoustic impedance and a hard surface of infinite acoustic impedance. The zones are arranged such that axisymmetry of the sound field is preserved. The equivalent source method is used to compute the sound field. It is shown that, by varying the sizes of the soft and hard zones on the sphere, a significant reduction can be achieved in the scattered acoustic power and upstream directivity when the sphere is near a free surface and its soft zone faces the incoming wave and vice versa for a hard ground. In both cases the size of the sphere’s hard zone is much larger than that of its soft zone. The boundary location between the two zones coincides with the location of a zero pressure line of the incoming standing sound wave, thus masking the sphere within the sound field reflected by the free surface or the hard ground. The reduction in the scattered acoustic power diminishes when the sphere is placed in free space. Variations of the scattered acoustic power and directivity with the sound frequency are also given and discussed.

CAER Authors

Avatar Image for Eldad Avital

Dr. Eldad Avital

Queen Mary University of London - Reader in Computational (& Experimental) Fluids and Acoustics

Share this

Next publication

2009 Psychology

The Dynamics of Category Conjunctions

R. Hutter, R. Crisp, G. Humphreys, Gillian. M. Waters + 1 more