Reflected Shock Tunnel Noise Measurement by Focused Differential Interferometry
Reflected Shock Tunnel Noise Measurement by Focused Differential Interferometry
复制标题
通过聚焦差分干涉法测量反射冲击隧道噪声
DOI：
10.2514/6.2012-3261
复制
发表时间：
2012
影响因子：
2.4
通讯作者：
H. Hornung
中科院分区：
文献类型：
--
作者：
N. Parziale;J. Shepherd;H. Hornung
进行了一系列实验，其中使用定量非侵入式光学技术来研究自由活塞驱动的反射激波风洞T5自由流中的扰动。光学技术，聚焦激光差示干涉(FLDI)，测量密度的波动。在测试矩阵中，当储层压力保持不变时，储层热焓是变化的。结果表明，密度扰动不是储集热的强函数。在一次实验中，检测到了异常水平的噪音；这种独特的结果归因于激波风洞的非理想操作。数据表明，在注意隧道清洁度的情况下，均方根密度波动小于0.75%是可以实现的。此外，密度波动的光谱含量在整个测试时间内不发生变化。
A series of experiments is conducted where a quantitative non-intrusive optical technique is used to investigate disturbances in the free-stream of T5, the free-piston driven reflected shock tunnel at Caltech. The optical technique, focused laser differential interferometry (FLDI), measures fluctuations in density. In the test matrix, reservoir enthalpy is varied while the reservoir pressure is held fixed. The results show the perturbations in density are not a strong function of the reservoir enthalpy. During one experiment, exceptional levels of noise were detected; this unique result is attributed to non-ideal operation of the shock tunnel. The data indicate that rms density fluctuations of less than 0.75% are achievable with attention to tunnel cleanliness. In addition, the spectral content of density fluctuation does not change throughout the test time.