Experimental Study of Spatial Structure Formation in Scalar-Vector Sound Fields Generated by a Towed Source in Shallow Sea

The results of experimental (simulation-based) modeling of the spatial structure of a scalar-vector sound field generated by a towed low-frequency source on the shelf of the Sea of Japan are discussed. Methodologically, the experiment involved towing a 134 Hz tonal source at a depth of 29 m along an acoustic path with variable bathymetry, at distances up to 10 km from a combined receiving system comprising a sound pressure sensor and three orthogonal components of the sound pressure gradient. Special attention is given to investigating the interference patterns of scalar and vector fields. Quantitative characteristics and features of interference formation at different depth sections of the path are discussed. Of particular interest are the unique results comparing horizontal and vertical field components, which confirmed the presence of vortex structures in the acoustic field of the source, a phenomenon previously identified by the authors in earlier studies on this topic. A hypothesis is proposed linking the emergence of the vertical field component to the slope of the waveguide seabed. The potential practical applications of the findings are analyzed.