Wavy Whiskers in Wakes: Explaining the Trail‐Tracking Capabilities of Whisker Arrays on Seal Muzzles

• Published in: Advanced science Vol. 10; no. 2; pp. e2203062 - n/a
• Main Authors: Zheng, Xingwen, Kamat, Amar M., Cao, Ming, Kottapalli, Ajay Giri Prakash
• Format: Journal Article
• Language: English
• Published: Germany John Wiley & Sons, Inc 01.01.2023; John Wiley and Sons Inc
• Subjects: Animals; Biomimetics; flow–structure interaction; Geometry; Hydrodynamics; Marine mammals; microelectromechanical system sensor; Microelectromechanical systems; Morphology; Phoca - anatomy & histology; seal whisker; Sensors; Swimming; Vibration; Vibrissae - anatomy & histology; vortex‐induced vibration; Vortices; wake‐induced vibration; United States > US; California; seal whisker; microelectromechanical system sensor; wake-induced vibration; vortex-induced vibration; flow-structure interaction
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202203062

Seals can detect prey up to 180 m away using only their flow‐sensing whiskers. The unique undulating morphology of Phocid seal whiskers reduces vortex‐induced vibrations (VIVs), rendering seals highly sensitive to biologically relevant flow stimuli. In this work, digital models of harbor and grey seal whiskers are extracted using 3D scanning and a mathematical framework that accurately recreates their undulating geometry is proposed. Through fluid–structure interaction studies and experimental investigations involving a whisker array mounted on 3D‐printed microelectromechanical systems sensors, the vibration characteristics of the whisker array and the interaction between neighboring whiskers in steady flows and fish‐wake‐like vortices are explained for the first time. Results reveal that the downstream vortices intensity and resulting VIVs are consistently lower for grey than harbor seal whiskers and a smooth cylinder, suggesting that the grey seal whisker geometry can be an ideal template for the biomimetic design of VIV‐resistant underwater structures. In addition, neighboring whiskers in an array influence one another by resulting in greater flow vorticity fluctuation and distribution area, thus causing increased vibrations than an isolated whisker, which indicates the possibility of a signal‐strengthening effect in whisker arrays. It is known that seals can detect prey up to 180 m away using their flow‐sensing whiskers, which feature undulating morphologies that reduce vortex‐induced vibrations. In this work, through fluidstructure interaction studies and experimental investigations involving seal whisker arrays mounted on 3D‐printed microelectromechanical systems sensors, the vibration characteristics of the whisker array and the interaction between neighboring whiskers in steady flows and fish‐wake‐like vortices are explained.