The three dimensionality of the intraglottal flow

Voice production depends critically on fluid–structure interactions within the glottis, especially during the closing phase of phonation where flow separation and pressure transients shape vocal output. We present a novel application of time-resolved tomographic particle image velocimetry (tomo-PIV) to visualize 3-D intraglottal airflow in opaque, anatomically realistic laryngeal models derived from high-resolution CT and dynamic stereo-DIC. Several glottal configurations representing mid-to-late closing phases were reproduced under controlled pressure conditions, and flow fields were reconstructed across the entire phonatory cycle. Phase-resolved flow rates showed strong agreement with known physiological waveforms. Notably, our results reveal entrainment zones, secondary separation, and vortex structures not typically captured in tissue-based models. These findings underscore the aerodynamic complexity of phonation and provide a validated physical platform for future model development and simulation benchmarking. This work builds a bridge between mechanical modeling and physiological relevance, offering new insights into the aerodynamic underpinnings of speech production. [Work funded by Grant R21 DC020275-01 from the National Institute on Deafness and other Communication Disorders (NIDCD), part of the National Institutes of Health (NIH).]