Biomimetic Riblets Inspired by Sharkskin Denticles： Digitizing, Modeling and Flow Simulation  

作　　者：Mariko Miyazaki Yuji Hirai Hiroshi Moriya Masatsugu Shimomura Akihiro Miyauchi Hao Liu 

机构地区：[1]Hitachi, Ltd., 832-2 Horiguchi, Hitachinaka, Ibaraki 312-0034, Japan [2]Chitose Institute of Science and Technology, 758-65 Bibi, Chitose, Hokkaido 066-8655, Japan [3]Tokyo Medical Dental University, 2-3-10 Kanda-Surugadai, Chiyodaku, Tokyo 101-0062, Japan [4]Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan

出　　处：《Journal of Bionic Engineering》2018年第6期999-1011,共13页仿生工程学报（英文版）

摘　　要：While sharkskin surface roughness in terms of denticle morphology has been hypothesized but remains yet controversial to be capable of achieving turbulent flow control and drag reduction, sharkskin-inspired ＂riblets＂ have been reported to be an effective biomimetic design. Here we address an integrated study of biomimetic riblets inspired by sharkskin denticles by combining 3D digitizing and mod- eling of＂fresh＂ denticles and computational fluid dynamic modeling of turbulent flows on a rough surface with staggered denticles and hound-tooth-patterned grooves. Realistic microstructures of denticles in five shark species of Galapagos, great white, whitetip reef, blacktip reef, and hammerhead sharks were first measured and digitized in three fold： （1） 2D imaging of lubricated sharkskin in a wet state by means of a ＂nano-suit＂ technique with a Field-Emission Scanning Electron Microscope （FE-SEM）; （2） 3D structures of sharkskin denticles with a micro-focus X-ray CT; and （3） single denticles of the five shark species in a 3D manner with 3D-CAD. The denticles at mid-body location in the five species were observed to have a structure of five non-uniform-ridges （herein termed ＂non-uniform grooves＂） with Angles Of Inclination （AOI） ranging over 20° - 32°. Hydrodynamics associated with the unique five-ridge denticles were then in- vestigated through modeling turbulent flow past a denticle-staggered skin surface. We further constructed a biomimetic riblet model inspired by the non-uniform grooves and investigated the hydrodynamic effects of height-to-spacing ratios of mid-ridge and side-ridges. Our results indicate that the morphological non-uniformity in sharkskin denticles likely plays a critical role in passively controlling local turbulent flow and point to the potential of denticle-inspired biomimetic riblets for turbulent-flow control in aquatic vehicles as well as other fluid machinery.While sharkskin surface roughness in terms of denticle morphology has been hypothesized but remains yet controversial to be capable of achieving turbulent flow control and drag reduction, sharkskin-inspired ＂riblets＂ have been reported to be an effective biomimetic design. Here we address an integrated study of biomimetic riblets inspired by sharkskin denticles by combining 3D digitizing and mod- eling of＂fresh＂ denticles and computational fluid dynamic modeling of turbulent flows on a rough surface with staggered denticles and hound-tooth-patterned grooves. Realistic microstructures of denticles in five shark species of Galapagos, great white, whitetip reef, blacktip reef, and hammerhead sharks were first measured and digitized in three fold： （1） 2D imaging of lubricated sharkskin in a wet state by means of a ＂nano-suit＂ technique with a Field-Emission Scanning Electron Microscope （FE-SEM）; （2） 3D structures of sharkskin denticles with a micro-focus X-ray CT; and （3） single denticles of the five shark species in a 3D manner with 3D-CAD. The denticles at mid-body location in the five species were observed to have a structure of five non-uniform-ridges （herein termed ＂non-uniform grooves＂） with Angles Of Inclination （AOI） ranging over 20° - 32°. Hydrodynamics associated with the unique five-ridge denticles were then in- vestigated through modeling turbulent flow past a denticle-staggered skin surface. We further constructed a biomimetic riblet model inspired by the non-uniform grooves and investigated the hydrodynamic effects of height-to-spacing ratios of mid-ridge and side-ridges. Our results indicate that the morphological non-uniformity in sharkskin denticles likely plays a critical role in passively controlling local turbulent flow and point to the potential of denticle-inspired biomimetic riblets for turbulent-flow control in aquatic vehicles as well as other fluid machinery.

关 键 词：SHARKSKIN denticles biommetic riblets 3D digitizing computational fluid dynamics 

分 类 号：TS941.734[轻工技术与工程—服装设计与工程] TQ320.662[化学工程—合成树脂塑料工业]