多孔介质对壁湍流边界层条带结构控制的机理研究

Based on the conservation equation of fluid flow in continuous medium, this project proposes that the turbulent drag reduction technique of porous media has the ability to change the dynamic behavior of physical quantities and the boundary conditions in the governing equations of fluid, by means of wind tunnel and numerical simulation. The volume force, induced vortex phenomenon and mechanism of porous media micro-jet were obtained. The phenomena of velocity slip and stress jump at the porous interface were studied. At the same time, the influence mechanism of two kinds of "disturbances" by porous media on wall turbulence streak structure was studied. The DMD dynamic mode reduction method was used to identify the streak structures accurately, and the development and evolution characteristics of the streak were obtained. Finally, research on parameters and control strategy is carried out..Controlling the structure of the near wall streak by flow control technique is an effective method to suppress turbulence and reduce friction. However, due to the complexity of wall turbulence control, how external control can interact with the streak to suppress turbulence burst, and the internal mechanism of controlling wall-bounded turbulence need further exploration. At the same time, how to improve the efficiency of control technology to the greatest extent is also a challenging problem which restricts the development of turbulent drag reduction technology. The research results will be of great academic value to the understanding and control of turbulent coherent structures in China, and will provide a new way to broaden the application of turbulent drag reduction technology and enhance the control ability.

通过流动控制技术控制近壁条带结构是抑制湍流、降低摩阻行之有效的方法。然而由于壁湍流控制的复杂性，外部控制如何与条带相作用，抑制湍流猝发、控制壁湍流的内在机理还有待进一步的探索。同时，如何提高控制技术的效率也是制约湍流减阻技术广泛开展的难题。本项目从连续介质流动的守恒方程出发，提出多孔介质湍流减阻技术兼具改变流体控制方程中物理量的动力学行为和改变边界条件的能力。通过风洞和数值模拟方法，获得多孔介质微射流产生的体积力、诱导旋涡现象和机制，并研究多孔界面产生的速度滑移和应力跳跃现象。同时，开展多孔介质两种“扰动”对壁湍流中条带结构的影响机制研究，通过DMD动力学模态降阶方法对条带进行准确识别，获得条带的发展、演化特性。最后，开展参数以及控制策略研究。研究成果将对我国湍流拟序结构的认识和控制有重要的学术价值，并将对拓宽湍流减阻技术的应用范围以及增强控制能力提供新的途径。

通过流动控制技术控制近壁条带结构是抑制湍流、降低摩阻行之有效的方法。本项目从连续介质流动的守恒方程出发，提出多孔介质湍流减阻技术兼具改变流体控制方程中物理量的动力学行为和改变边界条件的能力。项目开展多孔介质两种“扰动”对壁湍流中条带结构的影响机制研究，通过DMD动力学模态降阶方法对条带进行准确识别，获得条带的发展、演化特性。研究成果将对我国湍流拟序结构的认识和控制有重要的学术价值，并将对拓宽湍流减阻技术的应用范围以及增强控制能力提供新的途径。