Seal whiskers as a model system for flow dynamics and bio-inspired design

The whiskers (vibrissae) of some seal species have a unique undulated morphology that produces advantageous flow effects for bio-inspired engineering applications. This deceptively simple morphology has given rise to a variety of research directions and inspired novel data collection methods in order to explore the system in its full complexity. The undulated geometry is known to reduce vortex induced vibrations (VIV) by decorrelating the shed vortices along the whisker's trailing edge. The undulations themselves can be broken down into individual hydrodynamic features and our work considers how aspects of the geometry control VIV and drag reduction. Our research also highlights important considerations when targeting bioinspired engineering applications, including relative position of the geometry features to the flow and Reynolds number (Re) dependence of the observed effects. While the geometry substantially reduces VIV, it does not completely eliminate vibrations. A low-amplitude but spectrally rich vibrational signal remains, which serves as sensory input to the biological system. Interaction with flow and the disturbances encountered therein introduce energy into the system, which we observe through studies of the vibrational response. In this talk, we will explore the VIV reduction effects of the whisker geometry, the hydrodynamic detection potential of the whisker response, importance of array configurations, considerations of complexity of the complete system, and opportunities for study still offered by this rich biological model.