A Physical Model of the Vocal Folds

2003 ◽  
Author(s):  
Scott L. Thomson ◽  
Luc Mongeau ◽  
Steven H. Frankel
Keyword(s):  
Physical Model ◽  
Vocal Fold ◽  
Vocal Folds ◽  
Operating Conditions ◽  
Physical Models ◽  
Length Scale ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Voice Production ◽  
Flexible Polymer

Voice production is a result of the nonlinear, coupled interaction between laryngeal airflow and vocal fold tissue dynamics. Studying these fluid-structure interactions can contribute to the understanding of the mechanisms of speech production, leading to improved surgical, clinical, and pedagogical care. Aside from experiments using excised larynges (e.g., Berry et al., 2001) and a model of the superficial vocal fold layer (e.g., Chan et al., 1997), no studies appear to have been reported in which self-oscillating physical models were used that were similar to the human vocal folds in the following aspects: length scale, geometry, and dynamic and mechanical behavior. This paper describes a self-oscillating physical model designed to more closely represent the human vocal folds in terms of the above key parameters. The model was constructed using a flexible polymer casting and exhibited regular, self-sustained, large-amplitude oscillations at frequencies and operating conditions close to those found in human phonation. The model demonstrated potential for further studies involving laryngeal fluid-structure interactions.

Effect of Supraglottal Acoustics On Fluid-Structure Interaction During Human Voice Production

2021 ◽  
Author(s):  
Dariush Bodaghi ◽  
Weili Jiang ◽  
Qian Xue ◽  
Xudong Zheng
Keyword(s):  
Flow Rate ◽  
Vocal Fold ◽  
Splitting Method ◽  
Acoustic Resonance ◽  
Coupled Processes ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Voice Production ◽  
Acoustic Perturbation ◽  
Human Voice

Abstract A hydrodynamic/acoustic splitting method was used to examine the effect of supraglottal acoustics on fluid-structure interactions during human voice production in a two-dimensional computational model. The accuracy of the method in simulating compressible flows in typical human airway conditions was verified by comparing it to full compressible flow simulations. The method was coupled with a three-mass model of vocal fold lateral motion to simulate fluid-structure interactions during human voice production. By separating the acoustic perturbation components of the airflow, the method allows isolation of the role of supraglottal acoustics in fluid-structure interactions. The results showed that an acoustic resonance between a higher harmonic of the sound source and the first formant of the supraglottal tract occurred during normal human phonation when the fundamental frequency was much lower than the formants. The resonance resulted in acoustic pressure perturbation at the glottis which was of the same order as the incompressible flow pressure and found to affect vocal fold vibrations and glottal flow rate waveform. Specifically, the acoustic perturbation delayed the opening of the glottis, reduced the vertical phase difference of vocal fold vibrations, decreased flow rate and maximum flow deceleration rate at the glottal exit; yet, they had little effect on glottal opening. The results imply that the sound generation in the glottis and acoustic resonance in the supraglottal tract are coupled processes during human voice production and computer modeling of vocal fold vibrations needs to include supraglottal acoustics for accurate predictions.

scholarly journals Effect of Subglottic Stenosis on Vocal Fold Vibration and Voice Production Using Fluid–Structure–Acoustics Interaction Simulation

2021 ◽  
Vol 11 (3) ◽  
pp. 1221
Author(s):  
Dariush Bodaghi ◽  
Qian Xue ◽  
Xudong Zheng ◽  
Scott Thomson
Keyword(s):  
Flow Rate ◽  
Vocal Fold ◽  
Flow Resistance ◽  
Signal To Noise Ratio ◽  
Area Ratio ◽  
Subglottic Stenosis ◽  
Fluid Structure ◽  
Voice Production ◽  
Vocal Fold Vibration ◽  
Glottal Flow

An in-house 3D fluid–structure–acoustic interaction numerical solver was employed to investigate the effect of subglottic stenosis (SGS) on dynamics of glottal flow, vocal fold vibration and acoustics during voice production. The investigation focused on two SGS properties, including severity defined as the percentage of area reduction and location. The results show that SGS affects voice production only when its severity is beyond a threshold, which is at 75% for the glottal flow rate and acoustics, and at 90% for the vocal fold vibrations. Beyond the threshold, the flow rate, vocal fold vibration amplitude and vocal efficiency decrease rapidly with SGS severity, while the skewness quotient, vibration frequency, signal-to-noise ratio and vocal intensity decrease slightly, and the open quotient increases slightly. Changing the location of SGS shows no effect on the dynamics. Further analysis reveals that the effect of SGS on the dynamics is primarily due to its effect on the flow resistance in the entire airway, which is found to be related to the area ratio of glottis to SGS. Below the SGS severity of 75%, which corresponds to an area ratio of glottis to SGS of 0.1, changing the SGS severity only causes very small changes in the area ratio; therefore, its effect on the flow resistance and dynamics is very small. Beyond the SGS severity of 75%, increasing the SGS severity, leads to rapid increases of the area ratio, resulting in rapid changes in the flow resistance and dynamics.

Monitoring Vocal Fold Abduction through Vocal Fold Contact Area

1988 ◽  
Vol 31 (3) ◽  
pp. 338-351 ◽  
Author(s):  
Martin Rothenberg ◽  
James J. Mahshie
Keyword(s):  
Contact Area ◽  
Time Variation ◽  
Vocal Fold ◽  
Thyroid Cartilage ◽  
Electrical Conductance ◽  
Vocal Folds ◽  
Linear Phase ◽  
Voice Production ◽  
Voiced Speech ◽  
High Pass

A number of commercial devices for measuring the transverse electrical conductance of the thyroid cartilage produce waveforms that can be useful for monitoring movements within the larynx during voice production, especially movements that are closely related to the time-variation of the contact between the vocal folds as they vibrate. This paper compares the various approaches that can be used to apply such a device, usually referred to as an electroglottograph, to the problem of monitoring the time-variation of vocal fold abduction and adduction during voiced speech. One method, in which a measure of relative vocal fold abduction is derived from the duty cycle of the linear-phase high pass filtered electroglottograph waveform, is developed in detail.

Design of Apparatus for Studying Aerodynamics of Voice Production

2004 ◽  
Author(s):  
Michael Barry
Keyword(s):  
Flow Visualization ◽  
Vocal Fold ◽  
Sound Production ◽  
Vocal Tract ◽  
Vocal Folds ◽  
Flow Speed ◽  
Working Fluid ◽  
Voice Production ◽  
Experimental Apparatus ◽  
Glottal Flow

The design and testing of an experimental apparatus for in vitro study of phonatory aerodynamics (voice production) in humans is presented. The presentation includes not only the details of apparatus design, but flow visualization and Digital Particle Image Velocimetry (DPIV) measurements of the developing flow that occurs during the opening of the constriction from complete closure. The main features of the phonation process have long been understood. A proper combination of air flow from the lungs and of vocal fold tension initiates a vibration of the vocal folds, which in turn valves the airflow. The resulting periodic acceleration of the airstream through the glottis excites the acoustic modes of the vocal tract. It is further understood that the pressure gradient driving glottal flow is related to flow separation on the downstream side of the vocal folds. However, the details of this process and how it may contribute to effects such as aperiodicity of the voice and energy losses in voiced sound production are still not fully grasped. The experimental apparatus described in this paper is designed to address these issues. The apparatus itself consists of a scaled-up duct in which water flows through a constriction whose width is modulated by motion of the duct wall in a manner mimicking vocal fold vibration. Scaling the duct up 10 times and using water as the working fluid allows temporally and spatially resolved measurements of the dynamically similar flow velocity field using DPIV at video standard framing rates (15Hz). Dynamic similarity is ensured by matching the Reynolds number (based on glottal flow speed and glottis width) of 8000, and by varying the Strouhal number (based on vocal fold length, glottal flow speed, and a time scale characterizing the motion of the vocal folds) ranging from 0.01 to 0.1. The walls of the 28 cm × 28 cm test section and the vocal fold pieces are made of clear cast acrylic to allow optical access. The vocal fold pieces are 12.7 cm × 14 cm × 28 cm and are rectangular in shape, except for the surfaces which form the glottis, which are 6.35 cm radius half-circles. Dye injection slots are placed on the upstream side of both vocal field pieces to allow flow visualization. Prescribed motion of the vocal folds is provided by two linear stages. Linear bearings ensure smooth execution of the motion prescribed using a computer interface. Measurements described here use the Laser-Induced Fluorescence (LIF) flow visualization and DPIV techniques and are performed for two Strouhal numbers to assess the effect of opening time on the development of the glottal jet. These measurements are conducted on a plane oriented perpendicular to the glottis, at the duct midplane. LIF measurements use a 5W Argon ion laser to produce a light sheet, which illuminates the dye injected through a slot in each vocal fold piece. Two dye colors are used, one for each side. Quantitative information about the velocity and vorticity fields are obtained through DPIV measurements at the same location as the LIF measurements.

scholarly journals Effect of Dynamic Stress on Heavy Duty Centrifugal Pump Assembly through Fluid Structure Interaction.

2019 ◽  
Vol 8 (2S8) ◽  
pp. 1655-1659
Keyword(s):  
Centrifugal Pump ◽  
Dynamic Stress ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Water Current ◽  
Fluid Structure Interactions ◽  
Heavy Duty ◽  
Dynamic Stresses ◽  
Fluid Structure ◽  
Pump Assembly

The objective of the project is to reduce the vibration and fatigue in rotor of the centrifugal pump based on fluid structure interactions, when it rotates by the momentum of water current at different flow rate and to arrive at optimum operating conditions and perform structural analysis to determine deflection and frequency by using ANSYS 16.2.dynamic stresses are predicted at various nodal position, this would lead to suggest the method to reduce the frequency due to vibration.Computational fluid dynamics (CFD) study using Ansys 16.2 has been carried out to accomplish the objective of the work.

On the Mechanics of Phonation and Fluid-Structure Interactions in a Three Dimensional Vocal Fold Model

2007 ◽  
Author(s):  
Somesh Khandelwal ◽  
Thomas Siegmund ◽  
Steve H. Frankel
Keyword(s):  
Vibration Amplitude ◽  
Vocal Fold ◽  
Flow Model ◽  
Three Dimensional ◽  
The Self ◽  
Elastic Response ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Laminar Flow Model

It is hypothesized that the characteristics of vocal fold self oscillation is dependent on the nonlinearity of the solid structure i.e. the tissue. Studies of fluid structure interaction are conducted for three dimensional larynx models. Simulations were performed using the codes FLUENT and ABAQUS coupled by the code MpCCI. For the air an unsteady, laminar flow model was considered. Visco-hyperelasticity was used to characterize the solid domain representing the tissue structure. The computational model is used to conduct a parametric study on the self-oscillation response of the model with focus on the influence of the non-linearity in the hyperelastic response. Individual computations were compared by documenting the variation of the total energy of the structure. It is demonstrated that dissipation in the flow as well as the non-linearity in the elastic response all interact to stabilize or destabilize the vibration amplitude.

scholarly journals Energy-based fluid–structure model of the vocal folds

2020 ◽  
Author(s):  
Luis A Mora ◽  
Hector Ramirez ◽  
Juan I Yuz ◽  
Yann Le Gorec ◽  
Matías Zañartu
Keyword(s):  
Energy Exchange ◽  
Vocal Folds ◽  
Structure Model ◽  
Fluid Structure Interactions ◽  
Lumped Mass ◽  
Relevant Research ◽  
Mass Model ◽  
Fluid Structure ◽  
One Dimensional ◽  
Lumped Elements

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.

scholarly journals A Deep Neural Network Based Glottal Flow Model for Predicting Fluid-Structure Interactions during Voice Production

2020 ◽  
Vol 10 (2) ◽  
pp. 705
Author(s):  
Yang Zhang ◽  
Xudong Zheng ◽  
Qian Xue
Keyword(s):  
Neural Network ◽  
Flow Resistance ◽  
Deep Neural Network ◽  
Shape Function ◽  
Resistance Coefficient ◽  
Prediction Performance ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Voice Production ◽  
Glottal Flow

This paper proposes a machine-learning based reduced-order model that can provide fast and accurate prediction of the glottal flow during voice production. The model is based on the Bernoulli equation with a viscous loss term predicted by a deep neural network (DNN) model. The training data of the DNN model is a Navier-Stokes (N-S) equation-based three-dimensional simulation of glottal flows in various glottal shapes generated by a synthetic shape function, which can be obtained by superimposing the instantaneous modal displacements during vibration on the prephonatory geometry of the glottal shape. The input parameters of the DNN model are the geometric and flow parameters extracted from discretized cross sections of the glottal shapes and the output target is the corresponding flow resistance coefficient. With this trained DNN-Bernoulli model, the flow resistance coefficient as well as the flow rate and pressure distribution in any given glottal shape generated by the synthetic shape function can be predicted. The model is further coupled with a finite-element method based solid dynamics solver for simulating fluid-structure interactions (FSI). The prediction performance of the model for both static shape and FSI simulations is evaluated by comparing the solutions to those obtained by the Bernoulli and N-S model. The model shows a good prediction performance in accuracy and efficiency, suggesting a promise for future clinical use.

scholarly journals Effects of Sulcus Vocalis Depth on Phonation in Three-Dimensional Fluid-Structure Interaction Laryngeal Models

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Changwei Zhou ◽  
Lili Zhang ◽  
Yuanbo Wu ◽  
Xiaojun Zhang ◽  
Di Wu ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Vocal Folds ◽  
Threshold Pressure ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Phonation Threshold Pressure ◽  
Different Types ◽  
Sulcus Vocalis

Sulcus vocalis is an indentation parallel to the edge of vocal fold, which may extend into the cover and ligament layer of the vocal fold or deeper. The effects of sulcus vocalis depth d on phonation and the vocal cord vibrations are investigated in this study. The three-dimensional laryngeal models were established for healthy vocal folds (0 mm) and different types of sulcus vocalis with the typical depth of 1 mm, 2 mm, and 3 mm. These models with fluid-structure interaction (FSI) are computed numerically by sequential coupling method, which includes an immersed boundary method (IBM) for modelling the glottal airflow, a finite-element method (FEM) for modelling vocal fold tissue. The results show that a deeper sulcus vocalis in the cover layer decreases the vibrating frequency of vocal folds and expands the prephonatory glottal half-width which increases the phonation threshold pressure. The larger sulcus vocalis depth makes vocal folds difficult to vibrate and phonate. The effects of sulcus vocalis depth suggest that the feature such as phonation threshold pressure could assist in the detection of healthy vocal folds and different types of sulcus vocalis.

Simultaneous Tracking of Vocal Fold Superior Surface Motion and Glottal Jet Dynamics

2013 ◽  
Author(s):  
Joseph R. Nielson ◽  
David J. Daily ◽  
Tadd T. Truscott ◽  
Georg Luegmair ◽  
Michael Döllinger ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Particle Image ◽  
Vocal Folds ◽  
3D Flow ◽  
Time Resolved ◽  
Voice Production ◽  
Image Velocimetry ◽  
Subglottal Pressure ◽  
Superior Surface ◽  
Multiple Cycles

Synthetic aperture particle image velocimetry is used with an excised human vocal fold model to study the airflow between the vocal folds during voice production. A whole field, time-resolved, 3D description of the flow is presented over multiple cycles of vocal fold oscillations. The 3D flow data are synchronized with a 3D reconstruction of the superior surface of the vocal folds and with the subglottal pressure signal.

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