水下回转体首部超疏水表面边界层自然转捩机理的研究

水下回转体首部超疏水表面边界层自然转捩的机理，一方面与水下航行体首部流动噪声干扰声呐探测的技术瓶颈问题密切相关，有着重要的工程实际意义；另一方面处在超疏水表面流动转捩研究的前沿，有着重要的科学意义。本项目拟通过流动稳定性分析结合数值计算的方法，研究这一关键科学问题的四个方面。第一，确定超疏水表面对层流基本流的影响机理。第二，确定超疏水表面对小扰动失稳的影响机理。第三，确定超疏水表面对层流区壁面压力脉动的影响机理。第四，确定超疏水表面对自然转捩位置的影响机理。为了循序渐进，先对水下平板边界层进行研究，再对水下回转体首部边界层进行研究。拟通过上述研究，一方面在工程上，为解决首部流动噪声干扰声呐探测的实际问题提供基础支撑；另一方面在科学上，实现对超疏水表面流动自然转捩机理更深入、更全面、更系统的认识。

The natural transition mechanism in the bow boundary layers on superhydrophobic surfaces over an axisymmetric body in water is of great importance to both engineering and science. On the one hand, this problem plays a key role to the technical bottleneck problem, i.e. the flow noise at the forebody of an underwater vehicle disturbing sonar detecting. On the other hand, the problem is at the research forefront of the flow transitions on superhydrophobic surfaces. In the present project, we plan to investigate four aspects of this key scientific problem by doing instability analyses and numerical calculations. Firstly, it is expected to confirm the influence mechanism of the superhydrophobic surfaces on the laminar flows. Secondly, it is expected to confirm the influence mechanism of the superhydrophobic surfaces on the instability characteristics. Thirdly, it is expected to confirm the influence mechanism of the superhydrophobic surfaces on the pressure fluctuations on the wall in the laminar region. Fourthly, it is expected to confirm the influence mechanism of the superhydrophobic surfaces on the locations of natural transitions. We plane to start the research in the flat-plate boundary layers before the investigation in the bow boundary layers over an axisymmetric body. The present project has two aims in engineering and science. On the one hand, it aims to provide basic support to solve the engineering problem, i.e. the sonar detection being disturbed by the flow noise near the forebody of an underwater vehicle. On the other hand, it aims to develop and deepen our understanding of the natural transition mechanism of the flows on superhydrophobic surfaces.