Research on Manufacturing Vivid Trans-Scale Shark Skin Surface and Drag-Reducing Effect Simulation

摘要

Micro-grooves on the surface of shark skin scales can effectively inhabit the occurrence of turbulence and reduce the wall friction. But for the fluid mediums with high kinematic viscosity, the depth of the viscous sublayer will increase on the similar flow conditions, in order to enable the groove tips can stick out it, the size of scales must be enlarged. Therefore, in order to fit different fluid mediums, for purpose of reaching the best drag-reducing effect, the vivid shark skin scales should be amplified or deformed fabricated. By simplifying and magnifying the shark skin scales, many investigations have fabricated some kind of biomimetic shark skins. Whereas, the vivid trans-scale forming of biomimetic shark skin with surface morphology very close to the biological prototype is still an urgent problem to be solved. In this work, by high-precision scanning, data processing, model building and 3-D printing technology, the physical models of enlarged shark skin scales are machined. Additionally, for inspecting and verifying the drag reduction effect of trans-scale shark skin, the direct numerical simulation is carried out, and the drag reduction mechanism is also discussed and investigated comprehensively.