光学仪器, 2016, 38 (2): 159, 网络出版: 2016-06-06
基于动态散斑的颗粒流模式转变机理研究
Study on the mechanism of the pattern transition of granular flow based on the technique dynamic speckle
颗粒流 崩塌模式 连续流 过渡状态 动态散斑 granular flow avalanches pattern continuous flow transition regime dynamic speckle
摘要
颗粒流模式转变的研究具有重要的理论和现实意义,以滚筒内的颗粒流作为研究对象,采用动态散斑测量法研究了颗粒流的间歇崩塌和连续流动2种模式之间的转变机理。目的是利用动态散斑方法对滚筒颗粒运动进行研究,并尝试从两种状态持续时间的概率分布上对其转变机理做出阐述。通过CCD相机得到散斑图像,对散斑图像做对比度分析得到滚筒内颗粒运动速度跟时间的图像,进而提取出崩塌时间、连续时间、崩塌持续时间、崩塌间隔时间,并对其进行分布统计、曲线拟合、结果显示,两种状态转变不是突变性,而是存在一个2种状态共存的过渡状态,并且是随着各自的存在概率变大或者变小而逐渐地稳定下来。
Abstract
The research on the transformation of granular flow pattern has important theoretical and practical significance.This paper takes the granular flow in rotating drum as the research object,and uses the method of dynamic speckle (DS) measurement to study the transformation mechanism between the 2 modes of avalanches pattern and continuous flow pattern.The measurement of DS is used to study the transition phenomenon,and try to explain the mechanism of the transition from the two state duration probability distribution.The images of dynamic laser speckled by the CCD camera are obtained,and then the relationship between the moving velocity and time was figured out by the analysis of the contrast of dynamic laser speckle.The duration of discrete avalanches regime and continuous flow regime,duration of avalanche and avalanche interval were studied.By analyzing the statistical distribution of curve fitting,using the statistical results of the preceding,the characteristics are obtained.Results show that the two kinds of state transition is not mutation,but there is coexistence of the two states of the transition state,and follows their own existence probability becoming big or small and gradually stabilized.
马生, 杨晖, 李然, 盛旭波, 郑刚, 王世豪, 姚鑫. 基于动态散斑的颗粒流模式转变机理研究[J]. 光学仪器, 2016, 38(2): 159. MA Sheng, YANG Hui, LI Ran, SHENG Xubo, ZHENG Gang, WANG Shihao, YAO Xin. Study on the mechanism of the pattern transition of granular flow based on the technique dynamic speckle[J]. Optical Instruments, 2016, 38(2): 159.