EXCITATION OF AIR COLUMN IN A CLOSED TUBE BY TWO-DIMENSIONAL JETS

Abstract

The air column in the organ pipe is excited in acoustic oscillations by two-dimensional jets issuing from the flue slit. The large amplitude oscillations of the air column in the Hartmann generator or the Hartmann-Sprenger tube is also produced by air jets issuing from a cylindrical nozzle. The jet-drive mechanism of these oscillations has been investigated by many authors, and now we have reasonable explains for the fundamental mechanism of excitation. However, there is no complete explain on the mechanism of the change of oscillation modes or the transition of linear to non-linear oscillations caused by increasing of jet speed. The visualization results of two-dimensional jets driving the air column in the closed tube obtained in the present paper give useful informations for the analysis on the mechanism of the transition of linear to non-linear oscillations.