报告题目：the characteristics of flow around six in-line circular cylinders at low reynolds numbers
主讲人：tongming zhou教授
报告时间：2019年7月17日周三上午9:00-11:00
报告地点：轮机楼317会议室
主讲人简介：tongming zhou (周同明)，现任澳大利亚西澳大学土木、环境和采矿工程学院教师，博士生导师，工程和数学科学学院教学委员会委员。1987年在大连理工大学获得水利水电工程建筑专业工学学士学位，1989年在清华大学获得水力学及河流动力学工学硕士学位，1999年在澳洲newcastle大学获流体力学理学博士学位。2000年-2007年在新加坡南洋理工大学担任助理教授、副教授。从事的主要研究领域包括实验流体力学、流动控制、涡激振动、海洋能开发与利用等，负责多项政府和企业项目。发表学术论文近200篇，其中在流体力学和能领领域顶级期刊《journal of fluid mechanics》、《applied energy》等发表sci检索论文95篇，引用2000余次（h-index为25）。
报告摘要：flow past a circular cylinder has attracted significant amount of attention in fluid mechanics community due to its interesting phenomena and close relationship with industrial applications. when the number of cylinder is increased, the flow becomes more complex. this work investigates the characteristics of the flow field around a group of circular cylinders arranged in in-line configuration. a series of two-dimensional numerical simulations are carried out to simulate the flow for reynolds number in the range of 40 to 180 and gap to diameter ratio from 0.5 to 18. according to the vortex shedding characteristics around the six cylinders, a flow regime map is proposed where the flow is categorized into 4 different regimes, namely no-shedding regime, primary shedding regime, secondary shedding regime and tertiary shedding regime. before the transitions between flow regimes happen, shear layer re-attachment or extended shear layers are formed. for large gap to diameter ratios, the three vortex shedding regimes can co-exist and each regime dominates a region around the group of cylinders. the effect of the flow regime transition on vortex shedding frequency and force coefficients of each cylinder are quantified and explained. when the number of cylinders is increased further, the vortex shedding processes of the downstream cylinders become chaotic after transition to tertiary wake.
