Measuring glottal area and flow in an excised canine larynx model using stereoscopic particle imaging velocimetry.

Abstract

As opposed to the glottal area waveform, the opening and closing phases of glottal flow are asymmetric. Near the end of the closing phase, flow exiting the glottis has a rapid deceleration not seen during the opening phase; this “skewing” of the flow waveform is important for producing loudness and higher frequency harmonics. The major mechanism for the skewing of the flow waveform, relative to the area waveform, has been attributed to the nonlinear interaction between the vocal tract and the glottal flow. Previous work from this laboratory supports a hypothesis that both area and flow skewing are seen even without the vocal tract due to intraglottal flow separation vortices producing relative negative pressure. To help test this hypothesis in an animal model, a technique is necessary that can reliably measure glottal area and flow. In this work, we will show results for both glottal area and flow during phonation, in excised canine larynges, using stereoscopic particle imaging velocimetry and high speed visualization. The results support the hypothesis that intraglottal flow separation can be one mechanism for producing both flow and glottal skewing. [Work supported by NIDCD 5K08DC005421.]