Department of Engineering Physics, University of Wisconsin-Madison, Madison, WI, United States of America.
Naval Undersea Warfare Center, Newport, RI, United States of America.
PLoS One. 2020 Oct 29;15(10):e0241142. doi: 10.1371/journal.pone.0241142. eCollection 2020.
The complex undulated geometry of seal whiskers has been shown to substantially modify the turbulent structures directly downstream, resulting in a reduction of hydrodynamic forces as well as modified vortex-induced-vibration response when compared with smooth whiskers. Although the unique hydrodynamic response has been well documented, an understanding of the fluid flow effects from each geometric feature remains incomplete. In this computational investigation, nondimensional geometric parameters of the seal whisker morphology are defined in terms of their hydrodynamic relevance, such that wavelength, aspect ratio, undulation amplitudes, symmetry and undulation off-set can be varied independently of one another. A two-factor fractional factorial design of experiments procedure is used to create 16 unique geometries, each of which dramatically amplifies or attenuates the geometric parameters compared with the baseline model. The flow over each unique topography is computed with a large-eddy simulation at a Reynolds number of 500 with respect to the mean whisker thickness and the effects on force and frequency are recorded. The results determine the specific fluid flow impact of each geometric feature which will inform both biologists and engineers who seek to understand the impact of whisker morphology or lay out a framework for biomimetic design of undulated structures.
海豹胡须的复杂波浪形几何形状已被证明会极大地改变下游的湍流结构，从而与光滑胡须相比，减少水动力和改变涡激振动响应。尽管独特的水动力响应已经得到很好的证明，但对每个几何特征的流场影响的理解仍然不完整。在这项计算研究中，海豹胡须形态的无量纲几何参数是根据其水动力相关性定义的，使得波长、纵横比、波动幅度、对称性和波动偏移可以相互独立地变化。采用两因素部分因子设计实验程序创建了 16 个独特的几何形状，每个几何形状与基线模型相比都极大地放大或衰减了几何参数。对每个独特地形的流动使用大涡模拟进行计算，参考平均胡须厚度，记录力和频率的影响。结果确定了每个几何特征的具体流场影响，这将为试图了解胡须形态影响或为波浪形结构的仿生设计制定框架的生物学家和工程师提供信息。
