The Characteristics of Drag Reduction by Biomimetic Non-Smooth Surfaces

摘要

Drag resistances in the soil, fluid, or air bring us a lot of inconvenience. However, this problem which makes many troubles to scholars, engineers, and researchers, has been solved effectively by some animals or plant designed and optimized from the Nature. Through observing and investigating these phenomena, a special characteristic has been found that the bionic non-smooth configuration in the surface possesses the function of drag reduction. Based on imitating the geometrical morphology of the body surface of animals and plants, such as shark which living in the deep ocean and the dung beetle which living in the moist soil, many scientists made a lot of tests on various non-smooth surfaces not only in the fluid media but also in the soil media. Most of the experiments showed that the non-smooth surfaces have the characters of the drag reduction, or anti-adhesion, or minimizing friction between the interfaces. Till now, the mechanism of drag reduction is not known distinctly. Therefore, the simulations on the non-smooth surfaces are mechanical and passive. In order to take advantage of non-smooth phenomena in the engineering, which was brought by the nature, the investigating emphases should focus on the mechanism of drag reduction happened on different non-smooth surfaces and different medium in various condition.