【摘要】 从理论和实验两方面研究了不同温度下球形液滴的彩虹强度分布及在粒度测量中的应用。研究结果表明折射率为 1.33附近液滴在 117°～ 134°散射角范围内的散射强度分布不是单一的二阶彩虹强度分布 ,而是二阶和五阶彩虹的干涉强度分布。基于散射强度频谱特点 ,提出了一种从干涉强度谱中重建二阶和五阶彩虹强度分布的方法 :逆快速傅里叶变换 (IFFT)。利用洛伦兹米理论 (LMT)模拟计算了温度为 2 0℃和 80℃下水粒子二阶彩虹的高频结构与粒子直径的关系 ,获得了经验公式。该关系式可用来测量确定温度下均匀水粒子直径。还利用激光彩虹测试系统测量了水柱二阶彩虹角度范围内的散射强度分布。上述理论研究结果与实验结果进行了比较 ,两者吻合得很好。基于上述研究 ,可以从单一阵列探测器获取的彩虹信号提取不同阶次彩虹分布 ,用于液滴多参量的反演测量。更多还原

【Abstract】 This intensity distribution of rainbow at different temperature and its application in grain size measure are investigated theoretically and experimentally. The results show that scattering intensity distribution of droplet is not simply second-order rainbow distribution while refractive index is around 1.33 with scattering angle between 117° and 134°, but the interference distribution between second-order and fifth-order rainbow. According to the spectral characteristics of scattering intensity, the method of reconstructing intensity of the second order and fifth order rainbows from interference intensity spectrum is presented: inverse FFT. The relationship between ripple frequency of second order rainbow and grain diameter is simulated at 20 ℃ and 80 ℃ respectively by Lorenz-Mie theory, therefore the experimental formula is obtained to measure the diameter of homogeneous droplet at a certain temperature. The intensity distribution at second rainbow angles of droplets has been measured. The experimental result is in good agreement with the theoretical simulation. Based on this, the information of different orders of rainbow from the signal collected by only one detector is extracted.更多还原