活动地点：

活动类型：学术报告

主讲人：Gui-Qiang Chen

活动时间：

活动内容：

Title: Shock Reflection-Diffraction Phenomena,

        von Neumann's Conjecture,

        and Free Boundary Problems

 

 Speaker: Gui-Qiang Chen

Northwestern University (USA) & Fudan University (China)

 

 Abstract:

    In this talk we will start with various shock reflection-diffraction phenomena and their fundamental scientific issues. Then we will describe how the shock reflection-diffraction problems can be formulated into free boundary problems for nonlinear partial differential equations of mixed-composite hyperbolic-elliptic type and present the von Neumann's sonic conjecture. 

    The problems involve two types of transonic flow: One is a continuous transition through a pseudo-sonic circle, and the other is a jump transition through the transonic shock as a free boundary. 

    Finally we will discuss some  recent developments in attacking the shock reflection-diffraction problems, including some recent results on the existence, stability, and regularity of global solutions of shock reflection-diffraction by wedges.