CAREER: Hydrodynamic Sensing Mechanism of Seal Whisker

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Seal whisker sensing has recently attracted increasing research interest because of its extraordinary sensitivity and accuracy. Behavioral studies have demonstrated that blindfolded seals are able to use their uniquely-shaped whiskers to track hydrodynamic trails that were generated several minutes ago and discriminate the size and shape of upstream objects through their wakes. However, relatively little is known regarding the fundamental mechanisms driving the extraordinary sensing capabilities. The principal aim of this project is to advance our understanding of seal whisker sensing that result from its unique geometry by elucidating the roles of each geometric feature. The acquired knowledge will be transformative by inspiring innovative passive hydrodynamic sensing mechanisms associated with seal whisker geometry. The research will be integrated with a creative, bio-inspired engineering education plan to impact undergraduate and graduate engineering students, as well as students in grades 3-12, and the general public.The research will employ numerical fluid-structure interaction simulations to comprehensively characterize the individual and interactive effects of the geometric features of seal whisker on three aspects of its sensing, including (1) self-induced noises in calm waters caused by vortex-induced vibrations, (2) wake detection through wake-induced vibrations, and (3) whisker array signals. An in-house immersed-boundary-method based fluid-structure interaction solver will be used for parametric simulations of vortex-induced vibrations and wake-induced vibrations of a single whisker and multiple whiskers in wide ranges of geometric and flow parameters. The simulation results will be validated by comparing to the previously-obtained experimental measurements using the particle image velocimetry. The amplitude and frequency responses of the vibrations of different geometric models will be characterized in the parametric space. Empirical functions for vibration response characterizations will be derived. The underlying vortex dynamics and energy transfer mechanisms in terms of the interactions between the fluid forces and body displacement will be studied for understanding the vibration responses. The knowledge will not only inspire innovative hydrodynamic sensing mechanisms based on seal whisker geometry, but also contribute to the fundamental understanding of flow-induced vibration properties of bluff and slender bodies, which can have applications across broad engineering fields. The research will also investigate the signal patterns in the whisker arrays and their relationships with wake characteristics, which will have implications regarding the impact of array architecture in capturing wake information. This project is jointly funded by the Fluids Dynamics Program and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.