Fluid dynamic harmonica bending model

Bending is a phenomenon commonly used in the playing of diatonic harmonicas traditionally by changing the player’s mouth shape to lower the pitch of a specific note. It is always regarded as a technique specific to the harmonica family instead of being applicable to the entire free-reed instrument family. The cause has been studied and widely recognized as being the effect of acoustic feedback as well as the resonance of the double reed system inside a single hole of a harmonica. In recent years, the manufacturing technique of chromatic harmonica has improved enough that single reed bending has become more and more consistent. Without the second reed in resonance, the cause of single-reed bending has become complicated. We have proposed a work-in-progress model of reed activation and pitch bending based on our experimental data of pressure and velocity measurements on a single-reed 1:1 model. The sources of control in the experiments consist of both human breath and a fixed volumetric flow rate air inlet. We will also present particle image velocimetry measurements around a reed.