学术报告
Free Boundaries and Subsonic Jets - 辛周平教授 (香港中文大学)
题目：Free Boundaries and Subsonic Jets
报告人：辛周平教授 (香港中文大学)
简介：In this talk, I will discuss some issues concerning free boundary value problems associated with steady compressible subsonic jets forming from nite nozzle with given ambient pressure. Such a phenomena has important applications in sciences. Yet the mathematical formulation and analysis of such problems are quite subtle. I will present some recent progress on this problem for a two-dimensional nitely long convergent nozzle with straight solid wall. For such a nozzle, the jet problem can be formulated as follows: for the given ambient pressure and an incoming mass flux, one looks for a subsonic jet flow in a suitable space with the given incoming mass flux such that the flow velocity is in the normal direction at the inlet, the flow satisfies no-flow condition in the nozzle walls, and the flow reaches the ambient pressure at the free boundary. In general, the free boundary consist two distinct parts: one part is the partical path connecting the wall of the nozzle, and other part is a level set of the velocity potential. Such a free boundary value problem does not have a variational structure and there is no background flow to purturb. We will show that there is an optimal interval such that the jet problem has a unique solution when the length of the nozzle belongs to this interval and there is no such a solution otherwise. This talk is based joint works with ChunpengWang. This research is partially supported by Hong Kong RGC Earmarked Research grants CUHK-14305315 and CUHK-4048/13P, NSFC/RGC Joint Research Scheme N-CUHK443/14, and Focused Innovations Scheme from The Chinese University of Hong Kong.
时间：4月15日(周六)下午3:00-4:00
地点：首师大校本部新教二楼 511教室
欢迎全体师生积极参加！
