Lateral Cutoff Analysis and Results from NASA's Farfield Investigation of No-Boom Thresholds
Lateral Cutoff Analysis and Results from NASA's Farfield Investigation of No-Boom Thresholds
复制标题
美国宇航局对无繁荣阈值的远场调查的横向截止分析和结果
DOI：
10.2514/6.2016-3011
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Michael A. Hill
中科院分区：
文献类型：
--
作者：
L. Cliatt;E. Haering;Sarah R. Arnac;Michael A. Hill
为了支持美国国家航空航天局 (NASA) 将超音速商业旅行带给公众的持续努力，美国宇航局阿姆斯特朗飞行研究中心 (AFRC) 和美国宇航局兰利研究中心 (LaRC) 与其他行业组织和学术界合作，进行了一项飞行研究实验，以分析音爆地毯横向边缘的声学传播。这项工作的名称是法场无繁荣阈值调查 (FaINT)。该测试有助于建立一个数据集，该数据集将有助于进一步了解音爆地毯末端附近独特的声学传播特性。 FaINT 旨在收集整个横向截止过渡区域的精细空间音爆数据。这项工作的一个主要目标是研究音爆地毯可听边缘发生的声学现象，包括过渡区和阴影区。 NASA 的 F-18B 飞机进行超音速飞行，其音爆地毯过渡区将与 60 个麦克风、7500 英尺长的线性阵列相交。机翼上配备麦克风的 TG-14 机动滑翔机也试图捕捉与地面测量相同的音爆射线，海拔高度为 3000 - 6000 英尺。本文确定了过渡区和阴影区中音爆波形的适当度量标准，称为“感知声音暴露水平”，并确定了 65 dB 的值作为定义音爆噪声区域横向范围的声学水平限制；分析了音爆水平的变化，作为距地面和距地面 4500 英尺飞行路径距离的函数；并对音爆测量值和数值预测进行了比较。
In support of the ongoing effort by the National Aeronautics and Space Administration (NASA) to bring supersonic commercial travel to the public, the NASA Armstrong Flight Research Center (AFRC) and the NASA Langley Research Center (LaRC), in partnership with other industry organizations and academia, conducted a flight research experiment to analyze acoustic propagation at the lateral edge of the sonic boom carpet. The name of the effort was the Farfield Investigation of No-boom Thresholds (FaINT). The test helped to build a dataset that will go toward further understanding of the unique acoustic propagation characteristics near the sonic boom carpet extremity. The FaINT was an effort that collected finely-space sonic boom data across the entire lateral cutoff transition region. A major objective of the effort was to investigate the acoustic phenomena that occur at the audible edge of a sonic boom carpet, including the transition and shadow zones. A NASA F-18B aircraft made supersonic passes such that its sonic boom carpet transition zone would intersect a linear 60-microphone, 7500-ft long array. A TG-14 motor glider equipped with a microphone on its wing also attempted to capture the same sonic boom rays that were measured on the ground, at altitudes of 3000 - 6000 ft above ground level. This paper determined an appropriate metric for sonic boom waveforms in the transition and shadow zones called Perceived Sound Exposure Level, and established a value of 65 dB as a limit for the acoustic levels defining the lateral extent of a sonic boom's noise region; analyzed the change in sonic boom levels as a function of distance from flight path both on the ground and 4500 ft above the ground; and compared between sonic boom measurements and numerical predictions.