Recent biological studies have shown that harbor seals use their whiskers for underwater sensing and tracking of objects. They can track the wake of objects up to 35 seconds after the object has passed. This demonstrates the outstanding sensitivity of the harbor seal whisker as an underwater sensor. We aim to understand and apply this novel underwater sensing and tracking principle.
The above figures exhibit the main reason for the robustness in sensing. The geometry of the harbor seal whiskers is found to be unique. It is elliptical in its cross section while there are undulations on the major and minor axes along the length of the whiskers. These undulations serve to break the formation process of the vortices along the length of the whisker. Consequently, the forcing on the whiskers due to the vortex shedding becomes much weaker as compared to the case of elliptical or circular cylinder. As the self-induced vibration of the whisker is reduced due to weaker forcing, the whiskers have significantly lower noise as sensing devices.
Further studies are currently being performed to understand the role of the main features of the whiskers that significantly reduce the vortex-induced vibration of the whiskers.