The mechanical excitation of an acoustic resonance in a constant volume cavity

A standing half wave was excited in the column of ambient air within a long cylindrical tube, closed at both ends, by a longitudinal oscillation of the tube at the fundamental resonance frequency. For low amplitudes of oscillation the resonant behavior was adequately described by using linear acoustic theory. At high amplitudes shock waves appeared and the preliminary results generally agree with results for stationary tubes excited with a piston.This excitation apparatus is easy to build and operate. The constant volume cavity feature permits an accurate means of studying the non-linear shock wave behavior in various fluids at different pressures in the tube.