Acoustic surface wave measurements on live bottlenose dolphins

The surface wave velocity and absorption constant were determined on live bottlenose dolphins as a function of position, propagation direction, and frequency. A surface wave was propagated on the outer skin of a dolphin by an electromagnetic shaker driven by a noise source. Two miniature accelerometers were attached to the skin at a distance of 3.2 cm apart. The output signals from the accelerometers were analyzed by a dual‐channel fast Fourier transform spectrum analyzer. The data acquisition was further automated by a minicomputer. The surface wave velocities were the highest below the dorsal fin area and the lowest at an area around the posterior insertion of the pectoral fin. Generally, the velocity and absorption constant were independent of the propagation direction (anterior, posterior, dorsal, and ventral) except near the dorsal fin. Over most of the regions measured, the surface wave velocity ranged from 4 to 14 m/s over the frequency range of 20 to 1000 Hz. The attenuation α (dB/m) was assumed t...