多孔材料耦合吹吸气流控制钝体流动与噪声的研究

The porous material between fluid and solid, as a passive method of bluff body flow/noise control with great potential, is capable of stabilizing shear layer at the interface, suppressing vortex shedding, and regularizing wake field. However, the insufficiency of current experimental studies and the restrictions of high porosity and high layer thickness are hindering the understanding of the physical mechanism and its practical applications. On the basis of the experimental and numerical studies on flow around a cylinder with porous layer accomplished by the applicant’s team, this project proposes a comprehensive experimental study to address spanwise correlation in three-dimensional flow field, internal flow field within the porous layer and shear layer at the porous surface, as well as parameter effects. The proposed research will develop and complement the physical understanding of this control method, and validate and improve the numerical models of flow field and acoustic flied. Moreover, it is suggested to actively compensate the flow field within porous medium and the shear layer at porous surface using air blowing/suction. A new active/passive coupling control method will be developed and optimized that broadens the applicable conditions of porous material while retaining its advantages. Through integrating new experimental observations and new technique application, the research proposed in this project will reveal the physical process and scientific nature of bluff body flow and noise control by coupling porous material and air blowing/suction, and will provide theoretical and experimental foundation and technical support for the research and development of this new technology for reducing drag and noise.

介于流体和固体之间的多孔材料层能够有效稳定界面剪切层、抑制涡脱落、调控尾迹流场，从而降低气动阻力与噪声，是一种具有独特潜力的钝体流动与噪声被动控制方法，但现有实验研究的不足以及高孔隙率与高层厚的局限严重阻碍了此方法的机理认识和实际应用。本项目在申请人团队已完成的多孔层圆柱绕流实验与数值研究的基础上，开展三维流场展向相关性、多孔层内流场与表面剪切层、以及参数影响的实验研究，发展和补充此控制方法的物理认识，验证并改进流场与声场数值模型。同时，引入吹吸气流主动补偿多孔介质内部流场与表面剪切层，在保留多孔材料优势的同时拓宽其适用条件，发展新的主被动耦合控制方法并进行优化设计。本项目的研究融入了新的实验观测与新的技术应用，将深刻揭示多孔材料耦合吹吸气流控制钝体流动与噪声的物理过程和科学本质，为新概念减阻降噪技术研发提供理论实验依据与技术支撑。

多孔材料覆层能够有效稳定钝体表面剪切层、抑制涡脱落、调控尾迹流场，从而降低气动阻力与噪声，是一种具有独特潜力的流动与噪声被动控制方法。但现有研究对此方法的机理认识还不够充分，其实际应用也受制于高孔隙率和高层厚的局限。本项目围绕多孔覆层与吹吸气流的流动与噪声控制方法及其优化设计，结合实验测试与数值模拟，开展了多孔覆层流动与噪声控制的机理研究、多孔材料耦合吹吸气流的主被动控制研究、以及吹吸气流与主被动耦合控制的优化参数研究。本项目提出了结构化多孔材料的创新概念，完成了对圆柱绕流三维流场、多孔层近壁与内部流场、以及主要参数影响的系统全面的实验与数值研究，深入揭示了多孔材料控制钝体流动与噪声的作用机制，并获得了用于验证和改进数值模型的基准数据库。同时，研究了吹吸气流主动控制以及多孔覆层耦合吹吸气流的主被动方法对圆柱绕流的流动与噪声控制效果，并分析了其控制机理。在此基础上，获得了多孔覆层圆柱的优化布局与轻量化最优设计，研究分析了优化设计的流动与声学机理，进一步探索了吹吸气流和主被动耦合方法的优化参数及其控制机理。本项目的研究成果发展和补充了对多孔材料控制钝体流动与噪声的机理认识，并探索了利用吹吸气流耦合多孔材料进行流动与噪声控制的可行性，为发展主被动耦合降噪技术并推动其实际应用提供了有价值的理论与实验依据。

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