Directivity control of underwater sound reception inspired by the finless porpoise

The exceptional sound reception capabilities of odontocetes provide valuable inspiration for the design of advanced directional acoustic systems. Inspired by the sound reception system of the finless porpoise (Neophocaena asiaeorientalis sunameri), we developed a biomimetic receiver comprising artificial analogs of the mandible, external mandibular fat, and internal mandibular fat. The biomimetic external and internal mandibular fats were fabricated from soft silica gel, and the biomimetic mandible was made of aluminum. Simulation and experiment results demonstrate that the designed receiver enables effective control of underwater sound reception directivity. Specifically, widening the biomimetic external mandibular fat by 6.0 cm resulted in a 19.0° increase in the main beam angle and a 24.4° reduction in the 3-dB beam width at 25 kHz. Meanwhile, the biomimetic internal mandibular fat primarily functioned as a waveguide, effectively channeling acoustic energy. This receiver could serve as a useful tool for investigating odontocete sound reception mechanisms and has potential applications in underwater detection and communication.