Voice production is a result of the flow-structure interaction process in the larynx during which the glottal airflow causes the vocal fold tissue to vibrate more than 100 times per second. The objective of this research is to develop an accurate and yet efficient numerical approach to model the flow-induced vocal fold vibration and quantify the three-dimensional characteristics of the glottal flow and vocal fold dynamics. The numerical method will be based on an immersed-boundary method for incompressible flows with complex/moving boundaries and a nonlinear finite element method capable of representing large deformations of soft materials. Idealized geometry of the larynx will be adopted to simply the problem and to capture the key elements of the biophysics. Several important factors including the layered tissue structure, hyperelastic tissue behavior, large tissue strains, and vocal fold impact, will be incorporated to produce a realistic model.
Both the glottal flow and vocal fold vibration are highly three-dimensional, and their intriguing characteristics largely determine the unique features of an individuals voice (e.g., a soprano or tenor). The proposed research will reveal the underlying mechanisms that lead to the significant variations in the laryngeal dynamics. Specifically, the vortical structures in the flow, the oscillation mode of the vocal folds, and the impact stress on the vocal fold surface will be studied, and the effects of the laryngeal geometry and material properties of the tissue will be quantified. The conclusion drawn from the research will provide a much clearer understanding of the biophysics of phonation and will generate important guidelines for the future development of more advanced models useful in the clinical treatment of voice disorders. In addition, the flow field data produced in the numerical simulations can be used directly in the acoustic analysis of sound production in the larynx. To enrich the education of graduate and undergraduate students, a computational course incorporating multiphysics modeling will be created, which will address the interaction of fluids, thermal, structures, and electricity. Interactive online learning modules will be developed to reach out to K-12 students for them to learn interesting applications of fluid dynamics.
