Howard A. Stone教授学术报告通知

演讲题目：Elementary flows with surprising responses: (I) Biofilms and flow and (II) Trapping of bubbles in stagnation point flows

时间：2013年8月21日下午2：00-3:40

地点：浙江大学热能工程研究所205室

报告人：Prof. Howard A. Stone, Mechanical and Aerospace Engineering, Princeton University

摘要：

In this talk we describe two distinct problems that we have studied where seemingly modest variations in an elementary channel flow produce new effects. First, we investigate some influences of flow on biofilms. In particular, we identify the formation of biofilm streamers, which are filaments of biofilm extended along the central region of a channel flow, and show how these filaments are capable of causing catastrophic disruption and clogging of industrial, environmental and medical flow systems. We present a mathematical model to rationalize the rapid growth of the streamer. Second we consider flow in a T-junction, which is perhaps the most common element in many piping systems. The flows are laminar but have high Reynolds numbers, typically Re=100-1000. It seems obvious that any particles in the fluid that enter the T-junction will leave following the one of the two main flow channels. Nevertheless, we report experiments that document that bubbles and other low density objects can be trapped at the bifurcation. The trapping leads to the steady accumulation of bubbles that can form stable chain-like aggregates in the presence, for example, of surfactants, or give rise to a growth due to coalescence. Our three-dimensional numerical simulations rationalize the mechanism behind this phenomenon.

报告人简介：

Howard Alvin Stone is the Donald R. Dixon '69 and Elizabeth W. Dixon Professor in Mechanical and Aerospace Engineering at Princeton University. His field of research is in fluid mechanics, chemical engineering and complex fluids. He completed his undergraduate studies at University of California at Davis and earned his Ph.D. at the California Institute of Technology under the direction of L. Gary Leal. He joined Princeton in 2009 after twenty years of professorship at the School of Engineering at Harvard University, and after spending one year as a post-doctoral fellow in the Department of Applied Mathematics and Theoretical Physics at Cambridge University. His research has been concerned with a variety of fundamental problems in fluid motions dominated by viscosity, so-called low Reynolds number flows, and has frequently featured a combination of theory, computer simulation and modeling, and experiments to provide a quantitative understanding of the flow phenomenon under investigation. Stone's studies have been directed toward heat transfer and mass transfer problems involving convection, diffusion and surface reactions. He has made contributions to a wide range of problems involving effects of surface tension, buoyancy, fluid rotation, and surfactants. He has also studied problems concerning the flow of lipid bilayers and monolayers, and has investigated the motions of particles suspended in such interfacial layers. This research area is actively pursued by researchers at the interface of chemistry, physics and engineering. He is the recipient of the most prestigious fluid mechanics prize, the Batchelor Prize 2008, for best research in fluid mechanics in the last ten years and for his widely acknowledged leadership in fluid mechanics generally.

Selected Publications

1)        K. S. Ramamurthi, S. Lecuyer, H. A. Stone, and R. Losick, "Geometric Cue for Protein Localization in a Bacterium," Science 323 (5919), 1354-1357 (2009).

2)        E.Dressaire, R. Bee, D. C. Bell, A. Lips, and H. A. Stone, "Interfacial polygonal nanopatterning of stable microbubbles," Science 320 (5880), 1198-1201 (2008).

3)        A.S. Utada, E. Lorenceau, D. R. Link, P. D. Kaplan, H. A. Stone, and D. A. Weitz, "Monodisperse double emulsions generated from a microcapillary device," Science 308 (5721), 537-541 (2005).

4)        A.D. Stroock, S. K. W. Dertinger, A. Ajdari, I. Mezic, H. A. Stone, and G. M. Whitesides, "Chaotic mixer for microchannels," Science 295 (5555), 647-651 (2002).

5)        C. Duprat, S. Protiere, A. Y. Beebe, and H. A. Stone, "Wetting of flexible fibre arrays," Nature 482 (7386), 510-513 (2012)

6)        C. Duprat, S. Protiere, A. Y. Beebe, and H. A. Stone, "Wetting of flexible fibre arrays," Nature 482 (7386), 510-513 (2012)

7)        J. C. Bird, R. de Ruiter, L. Courbin, and H. A. Stone, "Daughter bubble cascades produced by folding of ruptured thin films," Nature 465 (7299), 759-762 (2010)    

8)        J. C. Bird, R. de Ruiter, L. Courbin, and H. A. Stone, "Daughter bubble cascades produced by folding of ruptured thin films," Nature 465 (7299), 759-762 (2010)    

9)        A.B. Subramaniam, M. Abkarian, L. Mahadevan, and H. A. Stone, "Non-spherical bubbles," Nature 438 (7070), 930-930 (2005).

10)    R. Dreyfus, J. Baudry, M. L. Roper, M. Fermigier, H. A. Stone, and J. Bibette, "Microscopic artificial swimmers," Nature 437 (7060), 862-865 (2005).

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