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2012 年 11 月 09 日
Seminar - Progresses and Perspective of Applied Mechanics by Prof. LI Jiachun

Date:   09 November 2012 (Friday)

Time:   11:00am –12:00 pm

Venue:  EF305, The Hong Kong Polytechnic University

Abstract:

Despite the success and mature of classic mechanics since Newton’s era, people were facing two great challenges of the Navier-Stokes equation origin at the turn of 19 ~ 20th century. Namely, why the transition from laminar flow to turbulence occurs as the Reynolds number exceeds a threshold and how the viscous drag of an object moving in fluid can be estimated? Then, L. Prandtl established the Department of Applied Mechanics in Gottingen and proposed Boundary Layer Theory (BLT) in 1904, right at the moment mankind eventually realized the first powered flight. Actually, BLT has created a new epoch of aeronautics. And Von Karman and his colleagues at CALTAC continued to break through sound and heat barriers by the end of 1940s so that a vehicle can flight at supersonic or even hypersonic speed, thus leading to mankind’s great achievements of aeronautics and aerospace engineering in the 20th century. As successors of Applied Mechanics School and founders of China’s modern mechanics, X.S. Tsien and his Chinese colleagues have made great contributions in promoting the advances of applied mechanics including Karman-Tsien formula, discovery of upper critical Mach number, establishment of hypersonic and rarefied flow branches, theory on thin shell stability, physical mechanics. Based on their in-depth study in this field, the scientists led by Tsien overcame the difficulties in rocket propulsion and thermal protection and attained great achievements of aerospace engineering in China during the second half of the 20th century. At the same time, various branches of applied mechanics are all in blossom. When looking into the future, the infrastructure on a large scale nowadays in China provides a good opportunity in many ways. The applied mechanics becomes more interdisciplinary so as to extend its applications to ocean and coastal engineering, environmental and energy engineering, chemical and material engineering and biomedical and microfluidics engineering. Moreover, the fundamental research in the behavior of complex and multiphase media from multi-scale viewpoint may help scientists to reveal various implied mechanisms. In particular, the combination of theory, computation and experiment/observation is extremely necessary in the exploration of new horizon in this perspective field.

Biosketch:

李家春教授是中国著名的力学家。 1940年7月26日生于上海。1962年毕业于复旦大学数学系。2003年当选为中国科学院院士。中国科学院力学研究所研究员,《力学与实践》主编。曾任科技部“九五”攀登项目“流体和空气动力学关键基础问题研究”首席科学家。

长期从事流体力学研究,在流动的非线性问题和力学中数学方法领域作出了理论成果。提出了摄动级数多对复奇点的判别准则最早用速度剪切解释有风时B-J不稳定的机理,得到弱风时不稳定加强,强风时不稳定抑制的新结论对自然环境中的波、流、涡、湍流进行了深入研究,解决与流体力学有关的诸如陆面过程、海气相互作用、台风异常路径、土壤侵蚀、海洋内波和波、流、结构相互作用等环境科学和海洋工程问题。