CAREER: Hydrodynamic Sensing Mechanism of Seal Whisker

近年来，海豹须传感以其非凡的灵敏度和准确性引起了越来越多的研究兴趣。行为学研究表明，蒙着眼睛的海豹能够利用它们独特形状的胡须追踪几分钟前形成的水动力轨迹，并通过尾迹辨别上游物体的大小和形状。然而，关于驱动非凡感知能力的基本机制，人们所知相对较少。该项目的主要目的是通过阐明每个几何特征的作用，提高我们对海豹须感应的理解。所获得的知识将通过激发与密封须几何形状相关的创新被动流体动力学传感机制进行变革。这项研究将与一个创造性的、以生物为灵感的工程教育计划相结合，以影响工程专业的本科生和研究生，以及3-12年级的学生，以及公众。本研究将采用数值流固耦合模拟的方法，全面表征海豹须的几何特征在三个方面的个体效应和交互效应，包括：(1)涡激振动在平静水域引起的自激噪声，(2)通过尾迹诱导振动进行尾迹检测，以及(3)须阵列信号。基于内部浸没边界法的流固相互作用求解器将用于在广泛的几何和流动参数范围内对单个晶须和多个晶须的涡激振动和尾迹激振进行参数模拟。仿真结果将通过与先前使用粒子图像测速法获得的实验测量结果进行比较来验证。不同几何模型的振动振幅和频率响应将在参数空间中得到表征。将推导振动响应表征的经验函数。为了理解振动响应，将研究流体力和体位移之间相互作用的潜在涡旋动力学和能量传递机制。这些知识不仅将激发基于密封须几何形状的创新流体动力传感机制，而且还有助于对钝体和细长体的流激振动特性的基本理解，这可以在广泛的工程领域得到应用。本研究还将研究晶须阵列中的信号模式及其与尾流特性的关系，这将对阵列结构对捕获尾流信息的影响产生影响。该项目由流体动力学计划和刺激竞争研究的既定计划（EPSCoR）共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.