基于序贯矢量平均的河流水面时均流场重建方法.doc.doc

基于序贯矢量平均的河流水面时均流场重建方法 张振1，陈红2，刘海韵1，石爱业1 （1. 河海大学计算机与信息学院，江苏 南京 211100； 2. 河海大学水利水电学院，江苏 南京 210098） 摘要：大尺度粒子图像测速（LSPIV）是一种新兴的瞬时全场流速测量技术。噪声区域性 关键词：大尺度粒子图像测速；河流水面；时均流场；平均策略 中图分类号：TH815 文献标识码：A 国家标准学科分类代码：510.40 A Sequential Vector Averaging Method for reconstructing time-averaged flow field of River Surface Zhang Zhen1, Chen Hong2, Liu Haiyun1, Shi Aiye1 （ of Computer and Information Engineering, Hohai University, Nanjing 211100, Nanjing; 2. College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, Nanjing） Abstract Large Scale Image Velocimetry (LSPIV) is a promising technique for measuring whole-field velocities instantaneously. However it suffers low flow field estimation precision in the application of natural rivers due to low seeding density, non-uniform tracer distribution and free-surface optical noises. By analyzing sensitivity of three time-averaged flow field reconstruction strategies, a method based on sequential vector averaging is proposed. It uses a nonlinear statistic-based global angle histogram method to detect the main flow direction according to the consistent distribution of cross-section velocity directions. Experiment results show that it is well suited for regional error vector identification in instantaneous flow field with low correct rate. Make use of the temporal-spatial redundancy information of flow tracers, the averaging process is controlled according to the correct rate of time-averaged flow field, which efficiently improves the temporal resolution of flow field. Key words：Large Scale Image Velocimetry; river surface; time-averaged flow field; averaging strategy 1　引言 天然河流的水文测验，特别是高洪期流速、流场及流量等信息的获取是洪水预报与防治的重要措施，以及河流水文学、河流动力学等研究的科学基础[1]。然而，天然河流中的水体在河槽中运动时受到断面形状、坡度、糙率、水深、弯道、风、气压、潮汐等因素的影响而产生紊流。紊流内部水质点的瞬时流速在大小和方向上均随时间变化，呈现出脉动现象，但在足够长的时段内其均值保持稳定[2]。因此，对于河流断面流量监测等应用而言，时均流场的重建比瞬时流场的获取更为重要。 作者简介：张振（1985-），男，江苏武进人，讲师，博士，主要从事光电成像与多传感器系统、大尺度粒子图像测速研究。 大尺度粒子图像测速（LSPIV）作为一种新兴的瞬时全场流速测量技术，不仅可用于常规条件下明渠紊动特性和时均特性的研究，其非接触特