Investigation of interference phenomena of vector field in shallow water

There exists stable interference pattern for broadband low frequency sound propagation in shallow water, the waveguide invariant concept is introduced to describe the interference structure of the acoustic pressure field in a waveguide and has been widely used in underwater acoustic applications. Acoustic vector sensor can measure the particle velocity in the ocean and provides more information for underwater acoustic applications. It is a meaningful work to introduce the waveguide concept into the vector field, and the investigation of vector field interference phenomena through numerical simulation is presented here. In this paper, the interference phenomena of broadband vector acoustic signals in shallow water are investigated by theory and numerical simulation. Energy spatial-frequency distributions for energy flux density which obtained by combination process of pressure and particle velocity signals are shown and analyzed. The advantages of the interference of vector field are indicated through the comparisons between the scale acoustic field and vector acoustic field. The waveguide invariant concept is then extended to describe the interference structure for range-depended environment.