Sound radiation from surface cutouts in high speed flow
Sound radiation from surface cutouts in high speed flow
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DOI：
10.7907/1crr-9y28
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发表时间：
1956
期刊：
影响因子：
--
通讯作者：
K. Karamcheti
中科院分区：
文献类型：
--
作者：
K. Karamcheti
在亚音速和超音速空气流通过切割成平面的矩形空腔的实验研究中，发现空腔发出强烈的声辐射。用热线在空腔中测得的发声振荡的频率与固定深度的宽度成反比。对于固定的宽度的频率被发现增加，但不是系统的，随着深度的减少。无因次频率S根据发射频率、差距宽度和自由流速度来定义。根据适当的实验，讨论了S对问题中的各种参数的依赖性，如马赫数、雷诺数和边界层厚度与空腔尺寸之比。通过马赫-曾德尔型的光学干涉仪获得辐射强度的估计。对于距离空腔3到4个空腔宽度处的点，在马赫数0.7到0.85时，从0.1英寸深和0.1到0.2英寸宽的空腔中产生的声场的强度为100 - 150分贝。讨论了腔体发声的可能机制。
In an experimental investigation of subsonic and supersonic flows of air past rectangular cavities cut into a flat surface it was discovered that the cavities emit a strong acoustic radiation. The frequency of the sound-producing oscillations measured by a hot wire in the cavity was found to be inversely proportional to the breadth for fixed depth. For fixed breadth the frequency was found to increase, though not systematically, with a decrease in depth. A non-dimensional frequency S is defined in terms of the frequency of emission, the gap breadth, and the free stream velocity. The dependence of S on the various parameters in the problem, such as Mach number, Reynolds number and ratio of the boundary layer thickness to a dimension of the cavity, is discussed in light of appropriate experiments. An estimate of the intensity of the radiation was obtained by means of an optical interferometer of the Mach-Zehnder type. For points located at 3 to 4 cavity breadths from the cavity, intensities of the order of 100 - 150 decibels were found for sound fields from cavities 0.1" deep and 0.1 to 0.2 inch broad at Mach numbers 0.7 to 0.85. Possible mechanisms for the sound production by the cavities are discussed.