Bulletin of the American Physical Society
75th Annual Meeting of the Division of Fluid Dynamics
Volume 67, Number 19
Sunday–Tuesday, November 20–22, 2022; Indiana Convention Center, Indianapolis, Indiana.
Session A07: Physiological, Phonation, and Speech |
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Chair: Rana Zakerzadeh, Duquesne University Room: 135 |
Sunday, November 20, 2022 8:00AM - 8:13AM |
A07.00001: Experimental validation of repeated /pa/ gestures for estimation of subglottal pressure with incomplete glottal closure Mohsen Motie-Shirazi, Matias Zanartu, Sean D Peterson, Byron D Erath Clinical estimation of subglottal pressure is a crucial metric for evaluating vocal efficiency, but remains difficult to quantitatively measure. Protocols for estimating subglottal pressure rely upon vocalizations where /pa/ is repeatedly phonated at a constant phonatory effort, and the intraoral pressure is recorded. It is assumed that the occluded intraoral pressure is the same as the subglottal pressure during the phonatory segment. The validity of this approach has been questioned in scenarios where incomplete glottal closure allows persistent flow leakage across the vocal folds, thereby changing the time-averaged flow resistance. In response, a benchtop synthetic vocal fold flow facility is utilized to quantify the temporal response of subglottal and supraglottal pressures during a simulated /pa/ gesture with leakage flow. Vocal efficiency and the time constant of the intraoral pressure response are quantified as a function of posterior glottal opening area. The results provide insight into clinical considerations that arise when estimating subglottal pressure with incomplete glottal closure, as well as the accuracy of this approach. |
Sunday, November 20, 2022 8:13AM - 8:26AM |
A07.00002: Expiratory noise due to subglottic stenosis using direct noise calculation Biao Geng, Qian Xue, Xudong Zheng, Scott L Thomson Subglottic stenosis (SGS) is the narrowing of the tracheal airway near the larynx. Characterization of the adventitious respiratory noise due to SGS could aid in its diagnosis. In this study, the SGS noise during expiration is simulated through direct noise calculation. The simulations are performed using a simplified axisymmetric airway geometry that includes the trachea, the vocal folds, the supraglottal tract, and open environmental space. The effects of stenosis severity and its distance from the glottis are investigated under various flowrates that cover the typical physiological range. Two glottal configurations, normal expiration and /h/ sound production, are considered to investigate the possibility of whistling due to Helmholtz resonance. The simulation setup is validated against experimental data in the literature using a Helmholtz resonator configuration to show the capability to capture the lock-on state between acoustic feedback and flow instability. The analysis is based on the statistically steady spectrum of the acoustic signal measured near the mouth. It is found that the overall noise level increases with flow rate and whistling only happens under restricted configurations. |
Sunday, November 20, 2022 8:26AM - 8:39AM |
A07.00003: Phonation energy budget estimated from acoustic field measurements Michael H Krane, John Kershner, Mitchell Swann, Paul Trzcinski The phonation energy budget estimated from measurements in a model of the human upper airway are presented. The model was comprised of a 2.54cm square duct, with molded rubber vocal folds that divided the duct into trachea and vocal tract sections. Synchronous measurements of pressure using two Kulite XCS-093 pressure transducers and 5 Larson-Davis ½” microphones, distributed over the length of the duct, and high-frame rate imaging of the glottis were performed for a range of subglottal pressures. Cross-spectral analysis of acoustic pressure measurements were used to extrapolate acoustic pressure and volume flow throughout the duct. This information was then used to compute terms of the cycle-averaged energy equation. |
Sunday, November 20, 2022 8:39AM - 8:52AM |
A07.00004: PhonoSim: a subject-specific modeling tool for pre-surgical planning of type I thyroplasty procedure Zheng Li, Mukund Gupta, Amit Avhad, Haoxiang Luo, Azure Wilson, Lea Sayce, Bernard Rousseau Type I thyroplasty procedure (TP) is widely used for the patients with unilateral vocal fold paralysis (UVFP) by inserting the implant into the paralyzed side of the vocal fold (VF). To improve the outcomes of TP, a suite of computational tool "PhonoSim" has been developed to simulate the fluid-structure interaction (FSI) of VF vibration under different configurations for pre-surgery planning. This suite includes different fidelity models for various purposes: an FEM model to reconstruct the subject-specific model based on MRI scan and conduct initial implant designs; a 1D flow model improved by machine learning coupled with 3D tissue model to adjust the tissue properties and further improve the implant design; a 3D FSI model to finalize the implant design. Our cross-disciplinary team has performed both numerical and experimental investigations on VF vibration in four configurations: rest configuration, two-side suture to mimic healthy phonation, one-side suture for UVFP, and one-side suture/one-side implant for TP surgery. Subject-specific model reconstruction is based on the rest configuration, while the other configurations are achieved by modeling the adduction process, which provides the pre-stress field within the tissue before FSI simulations. Larynges from rabbits were randomized to two groups: PhonoSim informed (n=6), and control (non-model informed, n=5) to perform TP. All six model-informed TP tests are successful while only one in control group is successful. Details of these computational components and their combination with the experiment study will be presented. |
Sunday, November 20, 2022 8:52AM - 9:05AM |
A07.00005: Success rate and repeatability of silicone vocal fold model fabrication Mohsen Motie-Shirazi, Qinwei Li, Byron D Erath Multi-layer synthetic silicone vocal fold (VF) models have been widely used for studying the physics of VF oscillations. These models are commonly fabricated by progressively pouring and curing layers of liquid silicone. However, despite their ubiquity and relatively long history of use in scientific investigations, investigators have reported that measures of oscillatory behaviors can vary widely for the same model/fabrication technique. Consequently, it is questioned how the skill and experience of the individual fabricating the models influence the outcomes. This was investigated by quantifying the fabrication success rate and the oscillatory characteristics of synthetic VF models made by three individuals with different levels of model-making experience; novice, intermediate, and advanced. Subjects were asked to fabricate 12 VF models following a detailed protocol. Models were evaluated at each step of fabrication according to predetermined quality measures. The models that passed were then evaluated by recording their phonation threshold pressure, flow rate, frequency, and glottal area. The fabrication success rate of the novice, intermediate, and advanced users was 0%, 17%, and 67%, respectively. The variability in the kinematic and aerodynamic measures of the successful VF models is also discussed. |
Sunday, November 20, 2022 9:05AM - 9:18AM |
A07.00006: Links between language, fluid dynamics, and the airflows that transport pathogens Junshi Wang, Simon Mendez, Haibo Dong, Howard A Stone Growing evidence shows that the airflows that accompany speech during social interactions contribute to the transport of pathogens, such as the SARS-CoV-2 virus. However, it is still elusive how the manners of articulation during speaking, such as time-varying airflow rate, and instantaneous teeth and lip movements, may affect the transport features of airflow exiting the mouth. We combine experimental and numerical approaches to investigate the flow patterns produced by representative vowels, such as /a/, /o/, and /i/, and consonants, such as /p/, /k/, /s/, and /h/, which have distinct articulatory characteristics. A 3D vocal tract is modeled with a temporally varying exit that captures key morphologic and kinematic features of the human vocal tract, including teeth and lips, during speaking. An incompressible flow solver based on a sharp-interface immersed-boundary-method (IBM) is employed to compute the resultant airflow. By comparing representative utterance pairs, like /apa/ and /aha/, we are able to isolate the effect of articulatory features and show significant differences in spatial-temporal patterns of airflow under the influences of a time-varying orifice, different orifice aspect ratios, and different relative lip-teeth positions. This work helps bring insights into the understanding of articulatory phonetics, and the links to different languages, from a fluid dynamics perspective. |
Sunday, November 20, 2022 9:18AM - 9:31AM |
A07.00007: Frequency dependence of glottal jet dynamics with full and incomplete closure Timothy Wei, Nathaniel J Wei, Abigail Haworth, Hunter Ringenberg, Michael H Krane This study focuses on frequency dependence effects on glottal jet dynamics with focus on the physiological condition where the vocal folds do not fully close. Incomplete closure occurs naturally, particularly in children and adult females. But there are also pathological conditions which can be problematic. Experiments were conducted using a 10x scaled-up model in a free surface water tunnel. 2-D vocal fold models with semi-circular medial surfaces were stepper motor driven with constant opening and closing speeds inside a square duct. Cases with complete vocal fold closure and incomplete closure to only 15% of the maximum gap were examined. Time-resolved DPIV, and pressure measurements along the duct centerline, were made at Re = 7200 over equivalent life frequencies from 52.5 Hz to 97.5 Hz. Phase-averaged and cycle-to-cycle analysis of key contributors to sound production was conducted. Acoustically relevant parameters, e.g., fluctuations in volume flow rate and transglottal pressure, are attenuated when vocal folds do not close completely. The key findings of this study, however, lie in statistical and dimensional scaling analysis of frequency dependencies of terms in the streamwise integral momentum equation. Specifically, the unsteady inertial term appears to become increasingly significant with increasing frequency and may be a key differentiator between lower frequency phonation, i.e. male voices, and the higher frequencies of children and adult females. These frequency effects, however, do not appear to be relevant to pathological conditions characterized by incomplete vocal fold closure. |
Sunday, November 20, 2022 9:31AM - 9:44AM |
A07.00008: A Fluid-Porous Structure Interaction Framework for Vocal Folds Rana Zakerzadeh, Durwash Badr, Isabella McCollum Flow-induced vibrations of the vocal folds produce a pulsatile jet that is the basic source of voiced speech. This study is focused on the computational investigation of interstitial fluid flow in the interaction between turbulent glottal airflow in the larynx and vibrating vocal fold during phonation, using a biphasic description of vocal fold tissue. This is necessary to accurately represent the true nature of vocal folds and investigate the effects of poroelasticity of the tissue on its liquid distribution and systemic hydration. The vocal folds deformation is modeled using the Biot system of equations for a poroelastic medium which defines the porous fluid flow by the Darcy equation. The computational model for the permeable vocal fold tissue is incorporated in fluid-structure interaction (FSI) methodology to compute the spatiotemporal interstitial liquid velocity as well as the pore pressure within the porous structure at multiple time points of the phonation cycle. Results are also compared for a range of lung pressures and tissue permeability values. |
Sunday, November 20, 2022 9:44AM - 9:57AM |
A07.00009: Fluid-structure-interaction and aero-acoustic simulations of vocal membrane vibration in the larynx of echolocating bats Chuanxin Ni, Jung-Hee Seo, Rajat Mittal Echolocating bats, despite their millimeter-size mammalian larynges, can produce ultrasound emissions with very high frequency and intensity. Bat larynges have a bilateral tissue structure called vocal membranes which are unique among mammals. Previous studies have argued that this structure might be responsible for the ultrasound generation and closely related to the ability of bats to precisely modulate the frequency of emitted signals. In the current study, a canonical bat larynx computational model is developed based on high-resolution micro-CT scans of a bat larynx. Fluid-structure-interaction simulations are carried out to study the effects of the vocal membranes on the flow field. Results of the energy extraction from the flow to the vocal membranes will be presented and the influence of the vibrating frequency and amplitude on the acoustic signals will be discussed. Implications of the vocal membrane vibration for the acoustic signal emission will also be examined. |
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