Alain Pumir：The Pirouette effect in turbulent flows

主讲人：Alain Pumir 教授
主持人：刘宗华 教授
开始时间：2013-12-04 14：00
讲座地址：闵行校区物理楼226报告厅
主办单位：物理系 科技处
报告人简介：
Alain  Pumir教授是法国Lyon高师非线性科学研究中心主任，国际著名的非线性科学与生物物理学专家，在物理学顶级学术  “物理评论快报”（PRL）等刊物上发表了一系列有广泛影响的论文，研究结果获得了国际同行的广泛关注，被邀请作国际会议学术报告40余次。是美国物理评论及非线性科学杂志的编委，获2008年度美国物理年会颁发的杰出审稿人奖。
报告内容简介：
The dynamics of the velocity gradient tensor plays a  crucial role in our understanding of turbulent flows. I will discuss recent  numerical and experimental results concerning the perceived velocity gradient  tensor, constructed with the help of 4 points (a tetrad). This tensor depends  on the overall size of the tetrad, thus permitting to study the properties of  the flow as a function of scale. I will in particular consider the statistical  properties, as well as the dynamical properties of the velocity gradient tensor,  in relation to the dynamics of the shape of the tetrad. These properties shed  some new light on the intriguing preferential alignment between vorticity and  the eigenvector, corresponding to the intermediate eigenvalue of the strain。