Shark skin exhibits a rather intriguing rib pattern which can help reduce drag. The bionic drag reduction has attracted the research interest of a lot of scientists in the last two decades. This paper looks into the detailed geometric profile of a real shark scale, and reports that the shark scale appears as matrices of numerous accrete structures which could enhance drag reduction. The sizes of these accreted structures range from 200 nm to 400 nm. The contribution of these structures to the drag reduction is analyzed by direct numerical simulation using the Computational Fluid Dynamics (CFD) software. Based on the results, it is found that such compound micro structures have higher performance than the previous patterns. In this paper, the models are fabricated by Ultra-precision manufacturing technologies, and the bionic models are tested in the low- speed wind tunnel to confirm the result of the simulation.
展开▼
