Sensing capabilites of bent Harbor Seal Whiskers*

Harbor seals utilize uniquely shaped whiskers to detect, locate, and follow prey, a remarkable adaptation that offers promising insights for advancing underwater sensing technologies. Our research has demonstrated that harbor seals' whiskers generate hairpin vortices, which reduce self-induced vibrations and enable the detection of small disturbances in the water. In nature, whiskers are not always perfectly straight, and this effect has long been overlooked in past studies. In this study, we aim to determine whether curvature in these whiskers affects the harbor seals' sensing capabilities. We conducted direct numerical simulations of flow past segments of both straight and progressively bent whiskers. Our findings revealed that bends in the whiskers disrupt the formation of hairpin vortices, increasing lift oscillation and therefore noises. Future studies are necessary to confirm that the observed effects are indeed due to the curvature of the whiskers and to quantify the effect of bends on lift oscillation and drag. Verifying these results will be crucial for understanding the precise role of whisker morphology in harbor seals' sensory abilities.