Blowing on a Bottle: Probing the Sound Generation Mechanics of Simple Resonators

Despite the simple design of instruments such as flutes, organs, whistles, and recorders, not all their sound-generation dynamics is understood. The excitation mechanics of these instruments resembles the phenomenon of blowing across the mouth of an empty bottle to induce sound from the bottle. For our experimental setup, such simple resonators were used to probe their sound-generation mechanics. Sound is produced only for certain values of the blowing velocity. Dimensional analysis suggests that these values of velocity scales with the frequency of sound being excited and a characteristic length of the mouth, irrespective of other geometrical details of the resonator. While this scaling theory is applicable to many other related problems like flutter and fluid-structure vibrations, we use the instance of acoustic resonators for verification.