Key Laboratory of Microgravity, Institute of Mechanics, Chinese Academy of Science, Beijing 100190, China.
J Acoust Soc Am. 2011 Apr;129(4):1740-7. doi: 10.1121/1.3552886.
In this paper, numerical simulations are used to study the turbulent wind noise reduction effect of microphone windscreens with varying shapes and flow resistivities. Typical windscreen shapes consisting of circular, elliptical, and rectangular cylinders are investigated. A turbulent environment is generated by placing a solid circular cylinder upstream of the microphone. An immersed-boundary method with a fifth-order weighted essentially non-oscillatory scheme is implemented to enhance the simulation accuracy for high-Reynolds number flow around the solid cylinder as well as at the interface between the open air and the porous material comprising the windscreen. The Navier-Stokes equations for incompressible flow are solved in the open air. For the flow inside the porous material, a modified form of the Zwikker-Kosten equation is solved. The results show that, on average, the circular and horizontal ellipse windscreens have similar overall wind noise reduction performance, while the horizontal ellipse windscreen with medium flow resistivity provides the most effective wind noise reduction among all the considered cases. The vertical ellipse windscreen with high flow resistivity, in particular, increases the wind noise because of increased self-generation of turbulence.
本文通过数值模拟研究了不同形状和流阻率的传声器防风罩对湍流风噪声的降低效果。研究了由圆形、椭圆形和矩形圆柱组成的典型防风罩形状。通过在传声器上游放置一个实心圆柱来产生湍流环境。采用带五阶加权本质无震荡格式的浸入边界法，提高了模拟精度，以适应高雷诺数下实心圆柱周围以及防风罩的多孔材料与开放空气之间的流动。不可压缩流的纳维-斯托克斯方程在开放空气中求解。对于多孔材料内部的流动，求解了修正后的 Zwikker-Kosten 方程。结果表明，平均而言，圆形和水平椭圆形防风罩具有相似的整体风噪声降低性能，而中等流阻率的水平椭圆形防风罩在所有考虑的情况下提供了最有效的风噪声降低效果。特别是高流阻率的垂直椭圆形防风罩会由于湍流自激增加而增加风噪声。
