粒子像测速技术（PIV）和激光散斑测速技术（LSV）的实验研究

THE EXPERIMENTAL RESEARCH ON PARTICLE IMAGE VELOCIMETRY (PIV) AND LASER SPECKLE VELOCIMETRY (LSV)

本文应用粒子像测速技术（ＰＩＶ）和激光散斑测速技术（ＬＳＶ），对Ｒａｙｌｅｉｇｈ－Ｂｅｎａｒｄ对流流动进行测量。说明这两种技术原理和数据处理方法是相同的，他们的区别取决于源密度（Ｓ．Ｄ．）。当Ｓ．Ｄ．≤１时，是粒子像模式，当Ｓ．Ｄ．＞１时，则呈现激光散斑模式。实验表明，三次光脉冲系统比二次光脉冲系统在测量信噪比方面改善很多。

This paper presents the experimental research on the measurements of Rayleigh-Benard convection flow by the Particle Image Velocimetry (PIV) and Laser Speckle Velocimetry (LSV). The basic principle and processing method of data for these techniques are the same.The difference between PIV and LSV depends on the concentration of light scatters in the field, i.e.source density S.D. .When S. D. ≤1, the specklegrams contain particle images,when S.D. >1 a speckle pattern is formed.The experimental results show that the signal and noise ratio improves most significantly when a triple pulsed system is used in preferance to a doubled pulsed system.