Principles of Laser Anemometry
Principles of Laser Anemometry
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激光风速测量原理
DOI：
10.1007/978-1-4899-1271-8_6
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
L. Lading
中科院分区：
文献类型：
--
作者：
L. Lading
激光风速仪是一个领域，其特点是使用激光进行流体速度的局部非扰动测量。现代激光风速仪的起源可以追溯到是的和Cummins1的测量。他们对悬浮在流体管流中的小颗粒进行了光散射实验。在给定方向上散射的光将表现出定义明确的多普勒频移。该偏移通常太小而不能通过光信号的直接光谱分析来检测。然而，通过在光电检测器上将散射光与参考光束相干混合，可以获得以多普勒频移本身的频率振荡的拍频信号。照射流动的光束和参考光束来自同一激光器。参考光束在声光池中通过布拉格衍射进行频移。为了克服测量速度的符号模糊性而进行频率偏移的原理直到几年后才得到广泛应用。
Laser anemometry is an area characterised by the use of laser light for localised non-perturbing measurements of fluid velocity. The start of what could be called modern laser anemometry goes back to the measurements of Yea and Cummins1. They performed a light scattering experiment on small particles suspended in a fluid pipe flow. Light scattered in a given direction would exhibit a well-defined Doppler shift. The shift is generally too small to be detected by direct spectral analysis of the optical signal. However, by coherently mixing the scattered light with a reference beam on a photodetector it was possible to obtain a beat signal oscillating with the frequency of the Doppler shift itself. The light beam illuminating the flow and the reference beam came from the same laser. The reference beam light was frequency shifted by Bragg diffraction in an acousto-optic cell. The principle of frequency shifting in order to overcome the sign ambiguity of the measured velocity did not find widespread use until several years later.