应土木工程与力学学院、西部灾害与环境力学教育部重点实验室、湍流-颗粒研究中心青年研究员胡锐锋邀请，德州理工大学(Texas Tech University)机械工程系姚杰博士于10月12日作线上学术报告，欢迎广大师生参加。
- 报告题目：Vortex reconnection and turbulence cascade
- 报 告 人：姚杰 博士
- 报告时间：2022年10月12日上午10:00-12:00
- 报告地点：腾讯会议ID 236 159 527（密码：35532）
- 主 持 人：胡锐锋 青年研究员
报告人简介
Jie Yao obtained the B.S. in Nanjing University of Science and Technology in 2011 and an M.S. in University of Houston in 2013 and Ph.D. from Texas Tech University in 2019. After that, he becomes a Postdoctoral Researcher at Texas Tech University. Jie Yao’s expertise is in vortex dynamics, turbulence, and high-performance computing.
报告摘要
Reconnection is the process by which two approaching vortices cut and connect to each other. As a topologically changing event, it has been a subject of considerable fundamental interest for decades – not only in (classical) viscous flows but also in quantum fluids and numerous other fields, such as plasmas polymers, DNAs, and so on. For viscous fluid flows, reconnection is believed to play a significant role in various important phenomena, such as turbulence cascade, fine-scale mixing, and aerodynamic noise generation. We first delineate the underlying mechanism involved in vortex reconnection and its apparent role in turbulence cascade and finite-time singularity. Then we address the helicity dynamics involved in viscous reconnection occurring in evolutions of a trefoil knotted vortex and a Hopf-link. For both cases, we find that the global helicity H gradually decreases before reconnection but sharply increases during reconnection -- suggesting that H for viscous flows is not conserved. Finally, we briefly discuss our recent work on direct numerical simulation of wall-bounded turbulence flow at high Reynolds numbers.