报告人：美国布朗大学 Kenny Breuer 教授
主持人：郗恒东 教授
时 间：2019年10月14日 9:00-10:00（报告一）
10:30-11:30（报告二）
地 点：西工大友谊校区 航空楼A706
报告一
题 目：Aeromechanics of compliant membranes - from bat flight to flexible wings
摘 要：Bats are able to fly with extraordinary agility and maneuverability, partly due to their articulated and highly-compliant membrane wings. These membranes have complex anisotropic hyper elastic properties which can be controlled using embedded muscles that dynamically adjust the wing tension in response to the aerodynamic conditions. Here I will present data from measurements of bats during free flight in a wind tunnel, including measurements of their wing motion, and the role of these tension-controlling muscles. In addition, we have performed a variety of experiments and theory on the behavior of elastic extensible membrane wings that are both fixed and flapping, I will describe how the compliance affects the aerodynamic performance and how, by mimicking the role of the tension-controlling muscles seen in bat wings, we can influence the aerodynamics performance and the vortex shedding on membrane wings at high angles of attack.
报告二
题 目：The mechanics of bacterial flagellar locomotion in viscous and viscoelastic fluids.
摘 要：Despite the fact that the swimming of flagellated bacteria has been studied for almost fifty years, predicting their swimming in viscous and viscoelastic liquids is still surprisingly controversial. The source of the uncertainty lies in a variety for sources, including the physics of "tumbling" - when the bacterial flagellar bundle unravels - as well as the importance of non-Newtonian effects such as shear thinning and normal stresses. Here, I will report on a series of experiments in which we track individual bacteria as they move through viscous media with varying viscous and viscoelastic properties. in this manner, we can account for individual cell-to-cell variation, and we can tease apart the different influences of bulk viscosity, shear thinning, non-Newtonian normal stresses and the ways in which the run-tumble process changes as these fluid properties vary.
报告人简介:
Kenny Breuer received his ScB from Brown and his MSc and PhD from MIT. He spent nine years on the faculty of MIT in the department of Aeronautics and Astronautics, before returning to Brown in 1999, where he is currently Professor of Engineering. In 2010 he received a courtesy appointment as Professor of Ecology and Evolutionary Biology. From 2011 to 2014 he served as Senior Associate Dean of Engineering for Academic Programs. His research interests are in Fluid Mechanics covering a wide range of topics, including the physics of flows at micron and nanometer scales, animal flight (bat flight in particular), energy harvesting, and the physics and control of turbulent flows. He is author of over one hundred refereed technical publications, has edited and co-authored several books, including "Microscale Diagnostic Techniques", "A Gallery of Fluid Motion" and "Multimedia Fluid Mechanics". He is a fellow of the APS, ASME and Associate Fellow of AIAA.
