EXPERIMENTAL STUDY OF SCATTERING BY SPHERES EMBEDDED IN A SILICONE PLATE

It is well known that volume scattering can affect back-scattered high-frequency signals from the seabed. Due to the intricacy of the multiple scattering effects and the complexity of the seafloor as an acoustical system, it is important to validate a model for this phenomenon cautiously in the laboratory. The laboratory measurement setup consists of a water filled tank within which the device under test, a Silicone plate with embedded spheres, is placed. Broadband transducers and a pulser-receiver are used to carry out reflection experiments on the heterogeneous plate subjected to oblique incidence. The placement of the emitter and the receiver is symmetrical with respect to a vertical plane, perpendicular to the heterogeneous plate. Measurements were carried out at an angle of incidence varying from 10 to 65 degrees. A Silicone reference plate (without inhomogeneities) is available to perform calibration experiments. A homogenization model developed by Waterman and Truell is proposed to describe the multiple scattering in the heterogeneous material. 1