Visualization of weak shock waves emitted from a trombone.

Abstract

The coalesce of compression waves propagating in pipes into weak shock waves is one of the topics of shock wave dynamics. We have worked for weak shock waves generated in automobile exhaust pipe lines [Sekine et al. (1990)] and train tunnel sonic booms in Japanese high speed train entry into a long tunnel [Takayama et al. (1995)]. Hirschberg et al. (1996) reported, for the first time, the emission of weak shock waves from a trombone blown in ff and Pandya et al. (2003) visualized weak shock waves emitted from brass instruments. So far we understood, these belong to our continuous academic curiosity. It is a highlight of brass instruments to produce dramatizing sounds. In the 631-bar of the fourth movement of Mahler’s symphony No. 1, fff is specified for a third trombone. We then visualized, by using a set of 1 m diameter schlieren mirrors in schlieren optics and holographic interferometry, weak shock waves emitted from a trombone blown in ff and fff and measured pressure at the muzzle and horn and velocity at the horn.