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Deng JJ, Peterson SD. Examining the influence of epithelium layer modeling approaches on vocal fold kinematics and kinetics. Biomech Model Mechanobiol 2023; 22:479-493. [PMID: 36536195 PMCID: PMC10787511 DOI: 10.1007/s10237-022-01658-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 11/19/2022] [Indexed: 12/23/2022]
Abstract
Grouping the thin epithelium and thicker superficial lamina propria layers into a single cover layer has been widely adopted in finite element vocal fold models. Recent silicone vocal fold studies have suggested, however, that inclusion of a distinct epithelial layer leads to more physiologically representative motion. This study systematically explores the ramifications of incorporating an epithelial layer into a cover grouping for finite element vocal fold modeling. A membrane model for the epithelium is introduced to facilitate parametric investigation by reducing the mesh density requirement of the epithelium into a single infinitesimally thin layer. Excluding the epithelium entirely leads to increased energy in higher order modes and larger inferior-superior excursion of the folds. Integrating the epithelium into a cover layer with volume-weighted average stiffness results in similar kinematics to that of a model treating the epithelium as a distinct layer. However, the internal stress/strain and contact pressure during collision are higher, and viscous dissipation is lower, when the epithelium is integrated into the cover. Thus, careful treatment of the epithelium is recommended for finite element studies, particularly when employing the models for estimating measures dependent upon internal stress/strain and/or collision pressure, such as vocal dose.
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Affiliation(s)
- Jonathan J Deng
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - Sean D Peterson
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
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2
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Lamprecht R, Scheible F, Veltrup R, Schaan C, Semmler M, Henningson JO, Sutor A. Quasi-static ultrasound elastography of ex-vivo porcine vocal folds during passive elongation and adduction. J Voice 2022:S0892-1997(22)00386-1. [PMID: 36529564 DOI: 10.1016/j.jvoice.2022.11.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/24/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022]
Abstract
OBJECTIVES The elastic properties of the vocal folds have great influence on the primary sound and thus on the entire subsequent phonation process. Muscle contractions in the larynx can alter the elastic properties of the vocal fold tissue. Quasi-static ultrasound elastography is a non-destructive examination method that can be applied to ex-vivo vocal folds. In this work, porcine vocal folds were passively elongated and adducted and the changes of the elastic properties due to that manipulations were measured. METHODS Manipulations were performed by applying force to sewn-in sutures. Elongation was achieved by a suture attached to the thyroid cartilage, which was pulled forward by defined weights. Adduction was effected by two sutures exerting torque on the arytenoid cartilage. A series of ten specimens was examined and evaluated using a quasi-static elastography algorithm. In addition, the surface stretch was measured optically using tattooed reference points. RESULTS This study showed that the expected stiffening of the tissue during the manipulations can be measured using quasi-static ultrasound elastography. The measured effect of elongation and adduction, both of which result in stretching of the tissue, is stiffening. However, the relative change of specific manipulations is not the same for the same load on different larynges, but is rather related to stretch caused and other uninvestigated factors. CONCLUSION The passive elongation and adduction of vocal folds stiffen the tissue of the vocal folds and can be measured using ultrasound elastography.
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Affiliation(s)
- Raphael Lamprecht
- Institute of Measurement and Sensor Technology, UMIT TIROL - Private University for Health Sciences and Health Technology, Hall in Tirol, Austria.
| | - Florian Scheible
- Institute of Measurement and Sensor Technology, UMIT TIROL - Private University for Health Sciences and Health Technology, Hall in Tirol, Austria.
| | - Reinhard Veltrup
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, Head- and Neck surgery, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany.
| | - Casey Schaan
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, Head- and Neck surgery, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany.
| | - Marion Semmler
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, Head- and Neck surgery, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany.
| | - Jann-Ole Henningson
- Chair of Visual Computing, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany.
| | - Alexander Sutor
- Institute of Measurement and Sensor Technology, UMIT TIROL - Private University for Health Sciences and Health Technology, Hall in Tirol, Austria.
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Taylor CJ, Thomson SL. Optimization of Synthetic Vocal Fold Models for Glottal Closure. JOURNAL OF ENGINEERING AND SCIENCE IN MEDICAL DIAGNOSTICS AND THERAPY 2022; 5:031106. [PMID: 35832120 PMCID: PMC9132011 DOI: 10.1115/1.4054194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 03/23/2022] [Indexed: 06/15/2023]
Abstract
Synthetic, self-oscillating models of the human vocal folds are used to study the complex and inter-related flow, structure, and acoustical aspects of voice production. The vocal folds typically collide during each cycle, thereby creating a brief period of glottal closure that has important implications for flow, acoustic, and motion-related outcomes. Many previous synthetic models, however, have been limited by incomplete glottal closure during vibration. In this study, a low-fidelity, two-dimensional, multilayer finite element model of vocal fold flow-induced vibration was coupled with a custom genetic algorithm optimization code to determine geometric and material characteristics that would be expected to yield physiologically-realistic frequency and closed quotient values. The optimization process yielded computational models that vibrated with favorable frequency and closed quotient characteristics. A tradeoff was observed between frequency and closed quotient. A synthetic, self-oscillating vocal fold model with geometric and material properties informed by the simulation outcomes was fabricated and tested for onset pressure, oscillation frequency, and closed quotient. The synthetic model successfully vibrated at a realistic frequency and exhibited a nonzero closed quotient. The methodology described in this study provides potential direction for fabricating synthetic models using isotropic silicone materials that can be designed to vibrate with physiologically-realistic frequencies and closed quotient values. The results also show the potential for a low-fidelity model optimization approach to be used to tune synthetic vocal fold model characteristics for specific vibratory outcomes.
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Affiliation(s)
- Cassandra J. Taylor
- Department of Mechanical Engineering, Brigham Young University, 350 EB, Provo, UT 84602
| | - Scott L. Thomson
- Department of Mechanical Engineering, Brigham Young University, 350 EB, Provo, UT 84602
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Mora LA, Ramirez H, Yuz JI, Le Gorec Y, Zañartu M. Energy-based fluid-structure model of the vocal folds. IMA JOURNAL OF MATHEMATICAL CONTROL AND INFORMATION 2021; 38:466-492. [PMID: 34149312 PMCID: PMC8210679 DOI: 10.1093/imamci/dnaa031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 06/29/2020] [Accepted: 09/30/2020] [Indexed: 06/12/2023]
Abstract
Lumped elements models of vocal folds are relevant research tools that can enhance the understanding of the pathophysiology of many voice disorders. In this paper, we use the port-Hamiltonian framework to obtain an energy-based model for the fluid-structure interactions between the vocal folds and the airflow in the glottis. The vocal fold behavior is represented by a three-mass model and the airflow is described as a fluid with irrotational flow. The proposed approach allows to go beyond the usual quasi-steady one-dimensional flow assumption in lumped mass models. The simulation results show that the proposed energy-based model successfully reproduces the oscillations of the vocal folds, including the collision phenomena, and it is useful to analyze the energy exchange between the airflow and the vocal folds.
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Affiliation(s)
- Luis A Mora
- Department of Electronic Engineering, Universidad Técnica Federico Santa María, 2390123 Valparaiso, Chile
- Département AS2M, FEMTO-ST/ENSMM, Université de Bourgogne Franche-Comté, 25000 Besançon, France
| | - Hector Ramirez
- Department of Electronic Engineering, Universidad Técnica Federico Santa María, 2390123 Valparaiso, Chile
| | - Juan I Yuz
- Department of Electronic Engineering, Universidad Técnica Federico Santa María, 2390123 Valparaiso, Chile
| | - Yann Le Gorec
- Département AS2M, FEMTO-ST/ENSMM, Université de Bourgogne Franche-Comté, 25000 Besançon, France
| | - Matías Zañartu
- Department of Electronic Engineering, Universidad Técnica Federico Santa María, 2390123 Valparaiso, Chile
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Li Z, Chen Y, Chang S, Rousseau B, Luo H. A one-dimensional flow model enhanced by machine learning for simulation of vocal fold vibration. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 149:1712. [PMID: 33765799 PMCID: PMC7954577 DOI: 10.1121/10.0003561] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 01/25/2021] [Accepted: 02/01/2021] [Indexed: 06/02/2023]
Abstract
A one-dimensional (1D) unsteady and viscous flow model that is derived from the momentum and mass conservation equations is described, and to enhance this physics-based model, a machine learning approach is used to determine the unknown modeling parameters. Specifically, an idealized larynx model is constructed and ten cases of three-dimensional (3D) fluid-structure interaction (FSI) simulations are performed. The flow data are then extracted to train the 1D flow model using a sparse identification approach for nonlinear dynamical systems. As a result of training, we obtain the analytical expressions for the entrance effect and pressure loss in the glottis, which are then incorporated in the flow model to conveniently handle different glottal shapes due to vocal fold vibration. We apply the enhanced 1D flow model in the FSI simulation of both idealized vocal fold geometries and subject-specific anatomical geometries reconstructed from the magnetic resonance imaging images of rabbits' larynges. The 1D flow model is evaluated in both of these setups and shown to have robust performance. Therefore, it provides a fast simulation tool that is superior to the previous 1D models.
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Affiliation(s)
- Zheng Li
- Department of Mechanical Engineering, Vanderbilt University, 2301 Vanderbilt Place, Nashville, Tennessee 37235-1592, USA
| | - Ye Chen
- Department of Mechanical Engineering, Vanderbilt University, 2301 Vanderbilt Place, Nashville, Tennessee 37235-1592, USA
| | - Siyuan Chang
- Department of Mechanical Engineering, Vanderbilt University, 2301 Vanderbilt Place, Nashville, Tennessee 37235-1592, USA
| | - Bernard Rousseau
- Department of Communication Science and Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
| | - Haoxiang Luo
- Department of Mechanical Engineering, Vanderbilt University, 2301 Vanderbilt Place, Nashville, Tennessee 37235-1592, USA
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6
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Chen Y, Li Z, Chang S, Rousseau B, Luo H. A reduced-order flow model for vocal fold vibration: from idealized to subject-specific models. JOURNAL OF FLUIDS AND STRUCTURES 2020; 94:102940. [PMID: 32210520 PMCID: PMC7093056 DOI: 10.1016/j.jfluidstructs.2020.102940] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We present a reduced-order model for fluid-structure interaction (FSI) simulation of vocal fold vibration during phonation. This model couples the three-dimensional (3D) tissue mechanics and a one-dimensional (1D) flow model that is derived from the momentum and mass conservation equations for the glottal airflow. The effects of glottal entrance and pressure loss in the glottis are incorporated in the flow model. We consider both idealized vocal fold geometries and subject-specific anatomical geometries segmented from the MRI images of rabbits. For the idealized vocal fold geometries, we compare the simulation results from the 1D/3D hybrid FSI model with those from the full 3D FSI simulation based on an immersed-boundary method. For the subject-specific geometries, we incorporate previously estimated tissue properties for individual samples and compare the results with those from the high-speed imaging experiment of in vivo phonation. In both setups, the comparison shows good agreement in the vibration frequency, amplitude, phase delay, and deformation pattern of the vocal fold, which suggests potential application of the present approach for future patient-specific modeling.
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Affiliation(s)
- Ye Chen
- Department of Mechanical Engineering, Vanderbilt University, 2301 Vanderbilt Place, Nashville, TN 37235-1592
| | - Zheng Li
- Department of Mechanical Engineering, Vanderbilt University, 2301 Vanderbilt Place, Nashville, TN 37235-1592
| | - Siyuan Chang
- Department of Mechanical Engineering, Vanderbilt University, 2301 Vanderbilt Place, Nashville, TN 37235-1592
| | - Bernard Rousseau
- Department of Communication Science and Disorders, University of Pittsburgh
| | - Haoxiang Luo
- Department of Mechanical Engineering, Vanderbilt University, 2301 Vanderbilt Place, Nashville, TN 37235-1592
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Li Z, Chen Y, Chang S, Luo H. A Reduced-Order Flow Model for Fluid-Structure Interaction Simulation of Vocal Fold Vibration. J Biomech Eng 2020; 142:021005. [PMID: 31201740 PMCID: PMC7104766 DOI: 10.1115/1.4044033] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 05/30/2019] [Indexed: 01/04/2023]
Abstract
We present a novel reduced-order glottal airflow model that can be coupled with the three-dimensional (3D) solid mechanics model of the vocal fold tissue to simulate the fluid-structure interaction (FSI) during voice production. This type of hybrid FSI models have potential applications in the estimation of the tissue properties that are unknown due to patient variations and/or neuromuscular activities. In this work, the flow is simplified to a one-dimensional (1D) momentum equation-based model incorporating the entrance effect and energy loss in the glottis. The performance of the flow model is assessed using a simplified yet 3D vocal fold configuration. We use the immersed-boundary method-based 3D FSI simulation as a benchmark to evaluate the momentum-based model as well as the Bernoulli-based 1D flow models. The results show that the new model has significantly better performance than the Bernoulli models in terms of prediction about the vocal fold vibration frequency, amplitude, and phase delay. Furthermore, the comparison results are consistent for different medial thicknesses of the vocal fold, subglottal pressures, and tissue material behaviors, indicating that the new model has better robustness than previous reduced-order models.
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Affiliation(s)
- Zheng Li
- Department of Mechanical Engineering, Vanderbilt
University, 2301 Vanderbilt Place, Nashville, TN
37235-1592
| | - Ye Chen
- Department of Mechanical Engineering, Vanderbilt
University, 2301 Vanderbilt Place, Nashville, TN
37235-1592
| | - Siyuan Chang
- Department of Mechanical Engineering, Vanderbilt
University, 2301 Vanderbilt Place, Nashville, TN
37235-1592
| | - Haoxiang Luo
- Department of Mechanical Engineering, Vanderbilt
University, 2301 Vanderbilt Place, Nashville, TN
37235-1592
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8
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Sadeghi H, Döllinger M, Kaltenbacher M, Kniesburges S. Aerodynamic impact of the ventricular folds in computational larynx models. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 145:2376. [PMID: 31046372 DOI: 10.1121/1.5098775] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 04/01/2019] [Indexed: 06/09/2023]
Abstract
Ventricular folds (VeFs) act as passive, non-moving structures during normal phonation. According to the literature, VeFs potentially aid the flow-driven oscillations of the vocal folds (VFs) that produce the primary sound of human phonation. In this study, large eddy simulations were performed to analyze this influence in a numerical model with imposed VF motion as measured experimentally from a synthetic silicone vocal fold model. Model configurations with and without VeFs were considered. Furthermore, configurations with rectangular and elliptical glottis shapes were simulated to investigate the effects of three-dimensional glottal jet evolutions. Results showed that VeFs increased flow rate and transglottal pressure difference by a decrease in the pressure level in the ventricles immediately downstream of the VFs. This led to an increase in the glottal flow resistance, increased energy transfer rate between the flow and VFs, and a simultaneous decrease in the laryngeal flow resistance, which shows a higher amount of kinetic energy in the glottal flow. This enhancement was more pronounced in the rectangular glottis and varied with the subglottal pressure and VeF gap size.
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Affiliation(s)
- Hossein Sadeghi
- Divison of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Erlangen, Medical School at Friedrich-Alexander University Erlangen-Nürnberg, Waldstrasse 1, 91054 Erlangen, Germany
| | - Michael Döllinger
- Divison of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Erlangen, Medical School at Friedrich-Alexander University Erlangen-Nürnberg, Waldstrasse 1, 91054 Erlangen, Germany
| | - Manfred Kaltenbacher
- Institute of Mechanics and Mechatronics, Technical University Vienna, Getreidemarkt 9, 1060 Vienna, Austria
| | - Stefan Kniesburges
- Divison of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Erlangen, Medical School at Friedrich-Alexander University Erlangen-Nürnberg, Waldstrasse 1, 91054 Erlangen, Germany
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9
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Computational Models of Laryngeal Aerodynamics: Potentials and Numerical Costs. J Voice 2018; 33:385-400. [PMID: 29428274 DOI: 10.1016/j.jvoice.2018.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 01/04/2018] [Indexed: 11/23/2022]
Abstract
Human phonation is based on the interaction between tracheal airflow and laryngeal dynamics. This fluid-structure interaction is based on the energy exchange between airflow and vocal folds. Major challenges in analyzing the phonatory process in-vivo are the small dimensions and the poor accessibility of the region of interest. For improved analysis of the phonatory process, numerical simulations of the airflow and the vocal fold dynamics have been suggested. Even though most of the models reproduced the phonatory process fairly well, development of comprehensive larynx models is still a subject of research. In the context of clinical application, physiological accuracy and computational model efficiency are of great interest. In this study, a simple numerical larynx model is introduced that incorporates the laryngeal fluid flow. It is based on a synthetic experimental model with silicone vocal folds. The degree of realism was successively increased in separate computational models and each model was simulated for 10 oscillation cycles. Results show that relevant features of the laryngeal flow field, such as glottal jet deflection, develop even when applying rather simple static models with oscillating flow rates. Including further phonatory components such as vocal fold motion, mucosal wave propagation, and ventricular folds, the simulations show phonatory key features like intraglottal flow separation and increased flow rate in presence of ventricular folds. The simulation time on 100 CPU cores ranged between 25 and 290 hours, currently restricting clinical application of these models. Nevertheless, results show high potential of numerical simulations for better understanding of phonatory process.
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Smith SL, Thomson SL. Influence of subglottic stenosis on the flow-induced vibration of a computational vocal fold model. JOURNAL OF FLUIDS AND STRUCTURES 2013; 38:77-91. [PMID: 23503699 PMCID: PMC3596840 DOI: 10.1016/j.jfluidstructs.2012.11.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The effect of subglottic stenosis on vocal fold vibration is investigated. An idealized stenosis is defined, parameterized, and incorporated into a two-dimensional, fully-coupled finite element model of the vocal folds and laryngeal airway. Flow-induced responses of the vocal fold model to varying severities of stenosis are compared. The model vibration was not appreciably affected by stenosis severities of up to 60% occlusion. Model vibration was altered by stenosis severities of 90% or greater, evidenced by decreased superior model displacement, glottal width amplitude, and flow rate amplitude. Predictions of vibration frequency and maximum flow declination rate were also altered by high stenosis severities. The observed changes became more pronounced with increasing stenosis severity and inlet pressure, and the trends correlated well with flow resistance calculations. Flow visualization was used to characterize subglottal flow patterns in the space between the stenosis and the vocal folds. Underlying mechanisms for the observed changes, possible implications for human voice production, and suggestions for future work are discussed.
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Affiliation(s)
- Simeon L. Smith
- Department of Mechanical Engineering, 435 CTB, Brigham Young University Provo, UT 84602, USA
| | - Scott L. Thomson
- Department of Mechanical Engineering, 435 CTB, Brigham Young University Provo, UT 84602, USA
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Daily DJ, Thomson SL. Acoustically-coupled flow-induced vibration of a computational vocal fold model. COMPUTERS & STRUCTURES 2013; 116:50-58. [PMID: 23585700 PMCID: PMC3622264 DOI: 10.1016/j.compstruc.2012.10.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The flow-induced vibration of synthetic vocal fold models has been previously observed to be acoustically-coupled with upstream flow supply tubes. This phenomenon was investigated using a finite element model that included flow-structure-acoustic interactions. The length of the upstream duct was varied to explore the coupling between model vibration and subglottal acoustics. Incompressible and slightly compressible flow models were tested. The slightly compressible model exhibited acoustic coupling between fluid and solid domains in a manner consistent with experimental observations, whereas the incompressible model did not, showing the slightly compressible approach to be suitable for simulating acoustically-coupled vocal fold model flow-induced vibration.
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Affiliation(s)
| | - Scott L. Thomson
- Corresponding author. Tel.: +1 801 422 4980; fax: +1 801 422 0516 3
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