Nonlinear gas oscillations in pipes. Part 2. Experiment
Nonlinear gas oscillations in pipes. Part 2. Experiment
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DOI：
10.1017/s0022112074001030
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发表时间：
1974-03
影响因子：
3.7
通讯作者：
B. Sturtevant
中科院分区：
文献类型：
--
作者：
B. Sturtevant
实验研究了闭管和开管在谐振频率附近的强迫非线性声振荡。特别地，研究了端部有不同孔板的管道的运动，并与端壁反射系数可调的二阶和三阶运动理论进行了比较。我们发现，尽管在某些情况下，激波是从开放的一端发出的，但在一个开放的管中共振振荡表现出非常大的振幅。对于封闭管中的共振振荡，用孔板代替固体端壁的效果是降低在这些条件下发生的激波的振幅和加厚压缩部分。在开管和闭管实验中，通过将理论拟合到实验中来评估的反射系数都发现随着振幅的增加而增加，这与先前研究者的观察结果一致（Ingard & Ising 1967）。事实上，对于开放的一端，观察到同样的线性依赖于振幅，但比例常数是不同的。观察到给定孔板在开放端和封闭端谐振频率处的反射系数之间的质的差异；在开端频率下，给定孔板的反射不如在闭端频率下理想。讨论了反射系数随波形变化的含义。
Forced nonlinear acoustic oscillations near the resonant frequency of closed and open tubes are studied experimentally. In particular, the motion in tubes terminated with different orifice plates is studied, and comparison is made with second- and third-order theories of the motion which contain an adjustable end-wall reflexion coefficient. It is found that oscillations at resonance in an open tube exhibit remarkably large amplitudes despite the fact that in some cases shock waves are emitted from the open end. For oscillations at resonance in a closed tube, the effect of substituting an orifice plate for the solid end wall is to reduce the amplitude and thicken the compressive portion of the shock waves which occur under these conditions. In both the open-tube and closed-tube experiments the reflexion coefficients which are evaluated by fitting theory to experiment are found to increase with increasing amplitude, in agreement with the observations of previous investigators (Ingard & Ising 1967). In fact, for the open end the same linear dependence upon amplitude is observed, but the constant of proportionality is different. Qualitative differences are observed between the reflexion coefficients of a given orifice at the open-end and the closed-end resonant frequencies; at the open-end frequency the reflexion from the given orifice is less ideal than at the closed-end frequency. The implications of reflexion coefficients dependent on the wave forms are discussed.