报告题目：THE FLUID MECHANICS OF FOAMS            

   报告人：Stephen Howard Davis教授  美国西北大学

   时间：2017年9月25日（星期一）10：00-11：00

   地点：玉泉校区教5-333

报告摘要：

     Gas bubbles in a liquid constitutes a two-phase system. When the liquid fraction is very small, the bubbles crowd each other foaming polyhedral shapes separated by thin liquid films, a foam. Most past studies consider air-water foams laden with surfactants that immobilize the interfaces, and allow the foam to form static arrays which are studied for preferred shapes using minimum-surface -energy criteria.

     In the present talk the dynamics of clean ( surfactant-free ) foams are studied in two dimensions that lead to disordered evolutions driven by the thinning of the liquid films, the rupture of the films by van der Waals instabilities, and the long time fragmentation of the foam. This analysis depends on the development  of network numerical model from which one can extract statistical relations for the number of bubbles as a function of time. These results have application the evolution of metallic foams which if frozen give rise to porous solids having high strength and low weight useful in the construction of ship, aircraft, and rockets.

报告人简介：

   Prof. Stephen Howard Davis received his Ph.D. in Mathematics from the University of Rensselaer Polytechnic Institute in 1964. He is currently the Walter P. Murphy Professor of Engineering Sciences and Applied Mathematics, Mechanical Engineering and Chemical and Biological Engineering at Northwestern University. He is a member of National Academy of Sciences, National Academy of Engineering and American Academy of Arts and Sciences. He was the chief editor of JFM and was awarded the Fluid Dynamics Prize.