Bulletin of the American Physical Society
72nd Annual Meeting of the APS Division of Fluid Dynamics
Volume 64, Number 13
Saturday–Tuesday, November 23–26, 2019; Seattle, Washington
Session C29: Biological Fluid Dynamics : Phonation and Speech |
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Chair: Michael Krane, Penn State University Room: 611 |
Sunday, November 24, 2019 8:00AM - 8:13AM |
C29.00001: Control volume analysis of phonatory aerodynamics using velocity and pressure measurements Timothy Wei, Hunter Ringenberg, Nathaniel Wei, Dylan Rogers, Feimi YU, Lucy Zhang, Michael Krane In a collaborative effort, flow through simplified models of human vocal folds are being examined both experimentally and computationally.~ The experimental work described in this talk entails a 10x scaled-up model in a free surface water tunnel.~ In addition to the 10x physical scale, the reduced kinematic viscosity of water allows for a 1500x reduction in frequency to match the Reynolds numbers and reduced frequencies of human phonation.~ As such DPIV measurements, coupled with time resolved pressure measurements along the vocal fold model, have sufficiently high spatial and temporal resolution to accurately study the dynamics and energetics of the underlying fluid dynamics.~ This, in turn, provides direct linkage with aerodynamics analyses done using a matching computational model.~ In this study, we use integral control volume analysis in both the scaled-up physical experiment and the computational model to examine the momentum and energy balance in the flow.~ Specific analysis of the Bernoulli equation for a range of Reynolds numbers and reduced frequencies will be examined.~ Comparison with computational results and observations on the key phenomena related to phonation will be provided. [Preview Abstract] |
Sunday, November 24, 2019 8:13AM - 8:26AM |
C29.00002: Vocal Fold Trauma: Deleterious Compensatory Behaviors in Response to Benign Lesions Mohsen Motie-Shirazi, Byron Erath Abnormally high vocal fold (VF) contact pressures result in the formation of benign lesions such as polyps and nodules, which may produce highly asymmetric VF motion, disrupt glottal aerodynamics, and prevent VF closure. In response, compensatory behaviors, such as increasing the subglottal pressure, are often performed to maintain acoustic output. It is hypothesized that increased subglottal pressure leads to a deleterious cycle of higher contact pressure, and subsequently, additional VF trauma. The objective of this work is to quantify VF contact pressures during this common compensatory behavior. Four-layer synthetic VF models are fabricated and investigated in a hemilaryngeal configuration with the wall contact pressure measured at the midpoint of the VF contact zone. Three sizes of lesions are modeled by inserting a spherical ball in the mid anterior-posterior direction of the superficial lamina propria layer, below the epithelium. Contact pressure and radiated acoustic sound pressure level (SPL) are first measured in normal models with no lesion and then compared to those with a lesion, where the subglottal pressure is adjusted to match the radiated SPL between the two cases. Results demonstrate that localized lesion stiffness and compensations via subglottal pressure significantly alter the VF kinematics, producing much higher contact pressures that increase with lesion size. [Preview Abstract] |
Sunday, November 24, 2019 8:26AM - 8:39AM |
C29.00003: Reduced-order glottal airflow model enhanced by machine learning Zheng Li, Ye Chen, Haoxiang Luo Complementary to expensive 3D flow simulations, reduced-order glottal airflow models are useful in the simulation of vocal fold vibration for various purposes such as tissue property identification and optimization of surgical implants. Existing reduced-order models are typically based on the Bernoulli principle and have limited accuracy. In recent works, we have developed a novel one-dimensional flow model including pressure loss along the glottis and also the entrance effect. The model has shown advantages over the Bernoulli based model. In this work, we introduce machine learning to enhance this one-dimensional flow model. In particular, we firstly perform 3D fluid-structure interaction (FSI) simulation for vocal fold vibrations with different vocal fold stiffnesses and medial thicknesses. Using the 3D data, sparse regression is performed to estimate the loss coefficient and entrance effect parameter for the reduced-order flow model. We then combine this enhanced reduced-order flow model with 3D FEM tissue model to simulate the vocal fold vibration. In comparison with full 3D FSI model, very good agreements are achieved in terms of vibration amplitude, frequency, as well as phase delay of the medial surface in all cases considered. [Preview Abstract] |
Sunday, November 24, 2019 8:39AM - 8:52AM |
C29.00004: Acoustic coupling effect on glottal dynamics during phonation. Dariush Bodaghi, Weili Jiang, Qian Xue, Xudong Zheng In this study, a two-dimensional flow-structure-acoustics interaction computational model was utilized to examine the effect of the acoustic coupling on glottal dynamics during normal human phonation. An incompressible Navier-Stokes equation based flow solver, three mass based vocal fold model and a hydro/acoustic splitting method based acoustics solver were coupled for simulating the three-way interaction. The hydro/acoustic splitting method is first verified for low Mach number wall bounded flow against compressible N-S solutions obtained by using Fluent. Two simulation cases, with and without the acoustic coupling, were studied to identify the role of the acoustic coupling in normal phonation. The results indicate that, while the incompressible flow model could roughly capture basic glottal dynamics, the acoustic coupling has noticeable effects on both glottal flow and vocal fold dynamics. [Preview Abstract] |
Sunday, November 24, 2019 8:52AM - 9:05AM |
C29.00005: A framework for simulation of sibilant fricatives using implicit compressible flow solver HsuehJui Lu, ChungGang Li, Akiyoshi Iida, Tsukasa Yoshinaga, Kazunori Nozaki, Makoto Tsubokura A numerical framework for modeling the sibilant fricative production is built in this study. The implicit time scheme with immersed boundary method based on a hierarchical structure grid as well as the modified solution-limited time stepping method for the compressible flow are adopted. Firstly, the acoustic resonance generated from the flow around the single plate is simulated to validate the numerical scheme and the result shows that this framework is highly efficient and suitable for the massive parallelization system to tremendously save the calculation time. Then, the simulation for a simplified model of the sibilant /s/ is conducted and SPL profiles are in good agreement with the experimental results. Finally, the simulation for a realistic geometry of sibilant /s/ scanned from the human vocal tract is performed to demonstrate that this framework is capable of making a contribution to the dental treatment in the near future. [Preview Abstract] |
Sunday, November 24, 2019 9:05AM - 9:18AM |
C29.00006: Phonation energy budget computed from high-fidelity aeroelastic-aeroacoustic simulation Lucy Zhang, Feimi Yu, Michael Krane A rigorous accounting of phonation energy utilization is presented, using high-fidelity computer simulations. The simulation uses the modified immersed Finite Element (iFEM) formulation, supplemented by boundary condition control using Perfectly Matched Layers. Vocal folds mimic the swept-ellipse multilayer rubber model used in coordinated experiments. Simulations were run for a range of subglottal pressures. Simulation results are used to compute terms of the integral energy equation for the volume containing air in the larynx. Flow work terms in particular are decomposed to clarify power transfer mechanisms. The mechanism described by each energy equation term is then classified in terms of its role (input, output, loss). Laryngeal acoustic efficiency is also presented. [Preview Abstract] |
Sunday, November 24, 2019 9:18AM - 9:31AM |
C29.00007: Phonation aeroacoustic sources identified from simulation Feimi Yu, Lucy Zhang, Michael Krane The principal aeroacoustic sources in phonation are estimated from a high-fidelity computer simulation. The simulation uses an immersed Finite Element (iFEM) formulation, supplemented by boundary condition control using Perfectly Matched Layers. Vocal folds mimic the swept-ellipse multilayer rubber model used in coordinated experiments. Simulations were run for a range of subglottal pressures. For each simulation, the principal aeroacoustic sources were deduced: a volume source due to changes in vocal fold volume, and a dipole source associated with vocal fold drag. Recent arguments regarding the equivalence of vocal fold drag and transglottal pressure force, and the relationship between vocal fold drag and glottal volume flow are also evaluated. [Preview Abstract] |
Sunday, November 24, 2019 9:31AM - 9:44AM |
C29.00008: 2. Simultaneous measurements of vocal fold wall motion, aerodynamic and acoustic pressure, and volume flow Faith Beck, Paul Trzcinski, Adam Nickels, Zachary Yoas, Jeff Harris, Michael Krane Simultaneous measurements of acoustic pressure, transglottal pressure, volume flow, and vocal fold surface motion are reported. Measurements were conducted in a hemilarynx configuration consist of the Penn State Upper Airway Model (PSUAM), using a multilayer swept-ellipse vocal fold model. Pressure and volume flow measurements were conducted as described in other studies in the PSUAM, but vocal fold surface motion was also acquired by imaging the surface with three Vision Research v1212 high-speed cameras. The surface motion was estimated from the video using DaVis Strainmaster. Vocal fold motion is decomposed using POD and correlated to pressure and flow measurements. [Preview Abstract] |
Sunday, November 24, 2019 9:44AM - 9:57AM |
C29.00009: Vocal fold asymmetry effects on phonation aeroacoustic source strengths Paul Trzcinski, Zachary Yoas, Michael Krane Measurements of aeroacoustic source strengths in a physical model of the human airway are taken for variations in prephonatory mechanical symmetry. Opposing synthetic silicone vocal folds were placed in the Penn State Upper Airway Model (PSUAM) and subjected to various driving pressures for which fold oscillations occur. Vocal fold symmetry was varied by changing the multilayer structure between the two vocal fold models. For each vocal fold pair, measurements include unsteady transglottal pressure, acoustic pressure in the vocal tract and trachea regions, projected glottal area, and time-varying volume flow. In particular, transglottal pressure has been shown to be an accurate measure of vocal fold drag, the aeroacoustic source strength. Measuring vocal fold drag indicates how asymmetry affects phonatory sound production. [Preview Abstract] |
Sunday, November 24, 2019 9:57AM - 10:10AM |
C29.00010: 4. Phonation energy utilization and vocal efficiency estimated from measurements in a physical model of the human vocal system Michael Krane, Paul Trzcinski, Zachary Yoas Measurements performed in the Penn State Upper Airway Model of acoustic pressure, transglottal pressure, volume flow, and glottal area are presented. These are used to estimate flow work terms of the integral energy equation, applied to the vocal system, to identify principal power transfers during phonation. These terms are estimated for the larynx, the vocal tract, and complete system. Each power flow is then classified as an input, output, or loss mechanism, according to the sign of the average power transfer per cycle. Efficiencies for each subsystem, and the system as a whole, are then presented as the ratio of output to input power per cycle. [Preview Abstract] |
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