The discovery of the Mach reflection effect and its demonstration in an auditorium

This paper examines the historical background leading to the discovery of the Mach reflection effect and applies original documents from Mach's residue which are kept in the archives of the Ernst-Mach-Institut in Freiburg. Two experimental setups for the generation and demonstration of the Mach reflection effect, incorporating an overhead projector, are described: (a) Mach's historic mechanical shock wave reflection and interaction experiments with soot covered glass plates, performed in 1875. The Mach triple points sharply erase the soot which results in a residual picture of funnel-shaped V-formations. The head-on collision of two shock waves is marked as a narrow line of piled-up soot. (b) CalTech's hydraulic jump reflection experiments in a shallow ripple tank, performed during World War II. Regular reflection and its transition into a Mach reflection wave. Using a slightly inclined tank and providing a shoreline in the middle of the tank, Mach stem propagation slows down to zero when hitting the shore line and, therefore, can be observed live without the use of a slow motion technique.Visiting graduate student on an IAESTE grantThe International Mach Reflection Symposia have been held in Victoria, BC, Canada (1981); Sydney, Australia (1982); Freiburg, FRG and Melbourne, Australia (1983); Tokyo and Sendai, Japan (1984); Menlo Park, CA, USA (1985); Beer Sheva, Israel (1986); Albuquerque, USA (1987) and Toronto, Canada (1988)This article was processed using Springer-Verlag T_EX Shock Waves macro package 1990.