Pressure drag and noise level are two key parameters related to flow past a bluff body, thus various active and passive methods have been developed to reduce the drag and noise. The paper presents a passive method of simultaneously reducing the pressure drag and aerodynamic noise associated with flow past a smooth circular cylinder by placing a porous material plate (PMP) downstream the cylinder. Multi-points instantaneous wall pressure and far-field acoustic pressure have been measured in an anechoic wind-tunnel facility. The experimental results confirm that the PMP is effective to reduce both the pressure drag and the noise level, showing an attractive advantage compared with the impermeable splitter plate and porous coating. Parametric studies reveal effects of the pores per inch (PPI) of PMP, PMP-cylinder spacing and incoming flow velocity on the pressure drag and noise level.

中文翻译：

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下游多孔材料板同时降低圆柱体流阻和噪声的实验研究

压力阻力和噪声水平是与流过阻流体相关的两个关键参数，因此已经开发了各种主动和被动方法来降低阻力和噪声。本文提出了一种被动方法，通过在圆柱体下游放置多孔材料板 (PMP)，同时减少与流过光滑圆柱体相关的压力阻力和气动噪声。在消声风洞设施中测量了多点瞬时壁压力和远场声压力。实验结果证实，PMP能够有效降低压力阻力和噪声水平，与不渗透分流板和多孔涂层相比，显示出诱人的优势。参数研究揭示了 PMP 的每英寸孔径 (PPI)、PMP 气缸间距和传入流速对压力阻力和噪声水平的影响。