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一、引言采用激光多普勒流速测量法(LDA)可以不接触测定足够透明流体的流速,流速与地点和时间有关。这种测量法既可测量缓行流动、也可测量高超声范围的流动。该法在几乎所有的情况下均优于探头测量法,因为流动不会受测量装置的干扰。测量信号与流速呈线性关系且与周围条件(如压力、温度和密度)无关。由于测量体积小,在边界层附近,象探头不便
I. INTRODUCTION Using laser Doppler flow measurement (LDA), a sufficiently transparent fluid can be measured without contact, and its velocity depends on the location and time. This method of measurement can measure both slow flow, but also measure the flow of high ultrasound range. This method outperforms the probe measurement in almost all cases because the flow is not disturbed by the measuring device. The measured signal is linear with the flow rate and is independent of the ambient conditions (eg pressure, temperature and density). As the measurement of small size, near the boundary layer, like the probe inconvenience