Hydrodynamics of flow past a bent seal whisker model

Harbor seals use uniquely shaped whiskers to detect, locate, and follow prey. This remarkable capability offers promising insights for advancing underwater sensing technologies. Previous studies have shown that these whiskers generate hairpin vortices, which help suppress self-induced vibrations and enhance sensitivity to subtle flow disturbances. However, in nature, seal whiskers are not always perfectly straight, and the impact of curvature on their sensing function has not been fully understood. In this study, we use direct numerical simulations to examine the flow over whiskers with varying degrees of curvature. Our findings reveal that bending in the whisker disrupts the formation of hairpin vortices and induces von Kármán vortex streets in the bent region instead. As a result, the lift oscillation, considered as the self-induced noise, is increased, which is not favorable for flow sensing. The findings provide new insights into how whisker morphology influences the sensory performance of seal whiskers and inform the design of whisker-inspired underwater sensors.