The suction force on the vocal folds as an energy source for vibration and as an acoustic source.

Abstract

It has been shown that single-degree-of-freedom vibration of sprung shutters in a duct with a source of constant pressure is enabled when there is a change in separation point position on the shutters [M. S. Howe and R. S. McGowan, Fluid Dyn. Res. in press]. In this scenario, the flow is supposed to separate on the upstream side of the shutters as they open and on the downstream side as they close. Energy is inputted from the flow into the shutters as the shutters close because of a suction force necessary to turn a potential flow around the edge of each shutter. This suction force is also called the Coanda force in the aerodynamics literature. This time variable suction force is a dipole source of sound that is distinct from drag force source that has already been discussed [M. S. Howe and R. S. McGowan, J. Fluid Mech. 592, 367–392 (2007)]. With these theoretical considerations, an equation analogous to Fant’s equation for the glottal jet can be derived to explore glottal jet kinematics and the effect of the time-varying glottal end correction on the jet just prior to closure. [Work supported by DC-009229 to UCLA under subcontract].