Nanoprobe Laboratory for Bio- and Nanotechnology and Biomimetics (NLBB), Ohio State University, 201 West 19th Avenue, Columbus, OH 43210-1142, USA.
Philos Trans A Math Phys Eng Sci. 2010 Oct 28;368(1929):4775-806. doi: 10.1098/rsta.2010.0201.
The skin of fast-swimming sharks exhibits riblet structures aligned in the direction of flow that are known to reduce skin friction drag in the turbulent-flow regime. Structures have been fabricated for study and application that replicate and improve upon the natural shape of the shark-skin riblets, providing a maximum drag reduction of nearly 10 per cent. Mechanisms of fluid drag in turbulent flow and riblet-drag reduction theories from experiment and simulation are discussed. A review of riblet-performance studies is given, and optimal riblet geometries are defined. A survey of studies experimenting with riblet-topped shark-scale replicas is also given. A method for selecting optimal riblet dimensions based on fluid-flow characteristics is detailed, and current manufacturing techniques are outlined. Due to the presence of small amounts of mucus on the skin of a shark, it is expected that the localized application of hydrophobic materials will alter the flow field around the riblets in some way beneficial to the goals of increased drag reduction.
快速游动的鲨鱼的皮肤具有沿流向排列的脊状结构，已知这些结构可减少湍流区的摩擦阻力。已经制造出一些结构来进行研究和应用，这些结构复制并改进了鲨鱼皮脊状结构的自然形状，最大阻力减少了近 10%。本文讨论了湍流中流体阻力的机制以及来自实验和模拟的脊状结构阻力降低理论。综述了脊状结构性能研究，并定义了最佳脊状结构几何形状。还对带有脊状结构的鲨鱼鳞片复制品的实验研究进行了调查。详细介绍了一种基于流体特性选择最佳脊状结构尺寸的方法，并概述了当前的制造技术。由于鲨鱼皮肤表面存在少量的黏液，因此可以预期，局部应用疏水性材料将以某种方式改变脊状结构周围的流场，从而有利于提高阻力减少的目标。
