Growth of Surface Waves with Application to the Mucosal Wave of the Vocal Folds

The initiation of surface waves over a layered structure is discussed. The analysis is done on a plane layered structure consisting of flowing air, epithelium, Reinke's space, and muscle. Only after the problem is solved for the homogeneous planar structure is a length scale imposed to determine a preferred wavelength, and the conditions for instability derived. Although the layered structure is a highly idealized version of the vocal folds, this analysis illuminates one type of instability allowing for the initiation of the mucosal wave. This same linear analysis can help us understand some of the dynamics of vibration during various parts of the glottal cycle. The method used is similar to that found in the linear analysis of flutter of aircraft panels.