The parametric propagation in underwater acoustics : experimental results

Abstract

In underwater acoustics, detection of buried objects in sediments (cables, mines, . . . ) is a complex problem. Indeed, in order to ensure sufficient penetration depth in marine sediments, low frequencies have to be used, implying a low resolution. A solution proposed to solve this problem is the parametric emission based on the nonlinear properties of seawater. This method can generate a low frequency wave from two directional high frequencies beams. The aim of this work is to present experimental results of a parametric propagation. Experiments have been carried out in a water tank in various configurations. These experimental measurements are then compared with simulation results obtained with a numerical model based on a fractional-step method presented at the Underwater Acoustic Measurements conference in 2011.