【作者】 徐津； 王玲玲；

【Author】 XU Jin;WANG Ling-ling;College of water Conservancy and Hydropower Engineering,Hohai University;State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering;

【机构】 河海大学水利水电学院； 水文水资源与水利工程科学国家重点实验室；

【摘要】 水流紊动结构与规律,对水体中传热传质特性有重要影响。本研究采用直接数值模拟方法,模拟了雷诺数为3300的明渠水流流动。针对流速、压力等物理量的非线性时间序列,运用相空间重构方法对紊动参量进行分析,并采用关联积分-关联维算法(C-C算法)计算这些物理量的时间延迟和嵌入维数。结果表明:对于特定雷诺数的充分发展的紊流,流速的脉动特征不会随时间发生变化,并且固壁会加剧水流的紊动。相空间重构技术是一种紊流研究的有效手段,可以定性地判定水流的紊动程度。更多还原

【Abstract】 The turbulence in the flow plays an important role in heat and mass transfer in water bodies.In this paper,direct numerical simulation(DNS) is used to study the channel flow under Reynolds number 3300.Phase-space reconstruction is applied to studying the nonlinear time series about velocities and pressure extracted from the numerical result.Thus,correspond integral-correspond dimension algorithm(C-C algorithm) is used to calculate the delay time and embedded dimension of those time series based on the phase-space reconstruction theory.Results reveal that the characteristics of turbulence are invariant with time as a fully-developed turbulent flow keeps the Reynolds number at constant.It can also be concluded that the reflection by the wall will increase the turbulence.Above all,phase-space reconstruction is a good tool to study the turbulent flow because it can quantify the turbulence in flows.更多还原