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2017-2018学年第二学期澳门太阳城第八期学术讲座
发表时间:2018-06-19 阅读次数:1132次

 

题目Rortex – A Third Generation and New Mathematical Definition of Vortex Vector and Vorticity Tensor and Vector Decompositions

主讲Professor Chaoqun Liu

主持徐弘一  研究员

时间2018年6月19日(星期二)下午14:00

地点澳门太阳城手机版邯郸校区光华楼东主楼2601室

 

个人简介

Dr. Chaoqun Liu received his BS degree in 1968, MS degree in 1981 from Tsinghua University, Beijing, China and his PhD degree in 1989 from the University of Colorado at Denver, Colorado, USA. He is currently a Distinguished Professor and the Director of Center for Numerical Simulation and Modeling at the University of Texas at Arlington, Arlington, Texas, USA. He has been working on high order direct numerical simulation(DNS) and large eddy simulation(LES) for flow transition and turbulence since 1990. As PI, he has been awarded with 50 federal research grants of over  5.7 million US dollars since 1990 in the United States. He has published 8 books, 96 journal papers and 139 conference papers. He also chaired the first and third US AFOSR International Conference on DNS/LES in 1997 and 2001, respectively. He is a well-established expert of high order DNS/LES for flow transition, turbulence, and shock and boundary layer interaction.

 

内容简介

A vortex is intuitively recognized as the rotational/swirling motion of the fluids. However, an unambiguous and universally-accepted definition for vortex is yet to be achieved in the field of fluid mechanics, which is probably one of the major obstacles causing considerable confusions and misunderstandings in turbulence research. A new vector quantity which is called Rortex is proposed as a mathematical definition of vortex vector to accurately describe the local fluid rotation and clearly display vortical structures. In this presentation, an eigenvector-based interpretation of Rortex is introduced as a mathematical definition: the real eigenvector of the velocity gradient tensor is served as the possible axis of the local fluid rotation to determine the direction of Rortex, and the rotational strength obtained in the plane perpendicular to the possible axis is defined as the magnitude of Rortex. In addition, new vorticity tensor and vector decompositions are introduced: the vorticity vector is decomposed to a rigidly rotational vector which is called the Rortex vector and a non-rotational vector which is called the shear vector.

 

(注:6月19日是徐弘一研究员主持的第八期学术讲座,6月22日是童崎青年研究员主持的第期讲座,此处更新上一则学术动态错误)

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