湍流边界层的电磁-沟槽复合控制与优化机理研究

With the development of avigation and navigation technology, the flow control has been the foreland and hotspot of hydrodynamics. There are many kinds of control approaches that have the different advantages and disadvantages. In the relative fields as avigation、navigation and so on, a single approach will not suffice for applications gradually. In order to make best use of the advantages and avoid the disadvantages, the different composite approaches should be adopted on the different conditions as different moments, locations and so on. The control of turbulence boundary layer is investigated mainly based by numerical calculations and theory analysis and verified by the composite actuators combining experiments, which aims for drag reduction in this project. The detail contents include: 1. The numerical calculations on the the composite control approaches of electromagnetic and groove. For different Reynolds numbers, the characters of flow field variations and interaction mechanism are revealed with the composed control approaches of electromagnetic and groove. 2. The investigations on the optimal composite control. The parameters, regions and strength of the composite control are optimal on the space and time. 3. Verification by experiments with the composite actuators.The variations of flow field and drag are investigated by the composite actuators mounted in the water tunnel, which is compared with the calculation results.The composite control approaches and the optimal control methods are known in this project，which guides a new thinking of further drag reduction and the decrease of energy consumption in many engineering projects of vortex-induced vibration, and it is of important practical values and academic significance.

随着航空航海技术的发展，流动控制已成为流体力学的前沿和热点问题,控制的方法也多种多样。而各种控制方法有着各自的优缺点,对于航空、航海等相关领域，单一的控制方法已逐渐无法满足实际需求。为了扬长避短，在不同的时刻、位置等条件下需采用不同的复合方式。本项目拟以理论研究和数值计算为主，并辅以实验验证，展开以减阻为目的的，复合激励板控制湍流边界层的研究。内容包括：1.电磁-沟槽复合控制的数值研究。揭示在不同雷诺数条件下的电磁-沟槽复合控制中，湍流流场的变化特征和耦合调制机理。2.复合控制的流动优化研究。从空间和时间上，对复合控制的组合参数、作用区域和作用强度进行优化。3.复合控制的实验验证。将复合激励板置入水洞中测试流场和阻力的变化,并与计算结果相互验证。该项目的开展可以认识复合控制的耦合机理和优化途径，对涡诱导的大量工程问题,进一步提高减阻效率和降低能耗提供新的思路，具有重要实用价值和学术意义。

随着航空航海技术的发展，流动控制已成为流体力学的前沿和热点。本项目以理论研究和数值计算为主，并辅以实验验证，展开以减阻为目的的，复合激励板控制湍流边界层的研究。主要创新性结果包括：(1)电磁-沟槽的复合控制机理研究。提出一种适用于变形壁面的谱方法求解算法，采用直接数值模拟，对不同参数下的电磁力与沟槽复合后对槽道湍流的控制效果进行了研究，找到了使得复合控制减阻率达到最大的最优控制参数，阐明了复合控制对槽道湍流的减阻机理。(2)不同雷诺数条件下的电磁力参数研究。通过数学推导、数值计算和实验相结合的方法，阐明展向电磁力参数对减阻率的影响，并找出最优控制参数，在不同雷诺数下对槽道湍流的最优控制参数变化特征，以及最优控制参数下近壁拟序结构随雷诺数的变化规律，从而揭示展向电磁力控制下减阻率随雷诺数变化的内在机理。(3)电磁力作用下槽道流速度响应的放大机理研究。以层流槽道流动作为研究对象，在槽道的下壁面施加沿展向余弦分布的展向电磁力，推导了线性条件下流向响应速度的解析解，并通过直接数值模拟对非线性条件下的响应进行了计算。结合解析解和数值解，揭示了流场中速度响应的放大机制，讨论了电磁力和流场参数对响应放大效果的影响。