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Date of Publication:2014-01-01

Journal:中国科技论文

Issue:8

Page Number:940-943

ISSN No.:2095-2783

Abstract:The skin surface of fast swimming shark’s is covered with grooves along the flow direction,which is proved to be able to reduce resistance in swimming.Using bionic technology,a series of trench structures with single scale is designed,such as V-shaped,L-shaped,U-shaped,etc.(defined as the original trench),and some drag reductions are acquired.Considering that the grooves covered on shark skin surface do not have a single scale,a secondary micro-grooved surface is designed in this paper by adding small-scale triangle on the top of the V-shaped grooves on both sides.Using RNG k-εturbulence model,the flow field of original V-shaped grooves and secondary micro-grooved surface were analyzed.With different Reynolds numbers,the effects of two trench walls on the velocity distribution in the turbulent boundary layer,shear stress of the trench wall and drag reduction were discussed.The results show that,in a certain range of Reynolds number,secondary micro-groove reduce the resistance by 8.07%,while the original V-shaped groove shorten the resistance by 4.6%.The secondary micro-grooved surface is more effec-tive in inhibit the turbulent flow in boundary layer and reduce the viscous resistance in fluid flow,and has a better drag reduction characteristics.

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