A Model and Vibrational Analysis of a Dolphin’s Acoustic System

Abstract

In this paper, a vibrational model of a dolphin’s acoustic system is presented. The working mechanism encompasses the dolphin’s lungs and nasal passage which hosts air pockets, the phonic lips, anterior and posterior bursae, the melon, lower jaw, and the brain. However, this study’s components of interest were the phonic lips, anterior bursa, and the surrounding muscle tissues. The phonic lips were modeled as rigid plates, surrounding muscles were modeled as springs, and the bursa was modeled as a damper. The chosen mechanical elements produced an underdamped system. There were two cases considered: a system in which the dolphin produces one click and a system in which the dolphin produces a series of clicks, called a click train. The former case is produced when the posterior phonic lip quickly and suddenly impacts the anterior phonic lip. Therefore, this was modeled as an impulse input. The latter case is produced when the posterior and anterior lip periodically engage one another. This was modeled as a sawtooth input. Using commercial computer software, a total of four different scenarios were considered, a healthy dolphin scenario and sick dolphin scenario for each input type.