Free boundary problems in shock reflection/diffraction and related transonic flow problems.
Shock waves are steep wavefronts that are fundamental in nature, especially in high-speed fluid flows. When a shock hits an obstacle, or a flying body meets a shock, shock reflection/diffraction phenomena occur. In this paper, we show how several long-standing shock reflection/diffraction problems can be formulated as free boundary problems, discuss some recent progress in developing mathematical ideas, approaches and techniques for solving these problems, and present some further open problems in this direction. In particular, these shock problems include von Neumann's problem for shock reflection-diffraction by two-dimensional wedges with concave corner, Lighthill's problem for shock diffraction by two-dimensional wedges with convex corner, and Prandtl-Meyer's problem for supersonic flow impinging onto solid wedges, which are also fundamental in the mathematical theory of multidimensional conservation laws.
Mathematical Institute, University of Oxford, Oxford OX2 6GG, UK chengq@maths.ox.ac.uk.
Gui-Qiang
http://orcid.org/0000-0001-5146-3839
GQ
Chen
Department of Mathematics, University of Wisconsin, Madison, WI 53706, USA.
Mikhail
M
Feldman
Lighthill's problem; equation of mixed elliptic–hyperbolic type; global entropy solutions; shock wave; transonic flow; von Neumann's problem