scholarly journals Impact of the Sub-Grid Scale Turbulence Model in Aeroacoustic Simulation of Human Voice

2021 ◽  
Vol 11 (4) ◽  
pp. 1970
Author(s):  
Martin Lasota ◽  
Petr Šidlof ◽  
Manfred Kaltenbacher ◽  
Stefan Schoder
Keyword(s):  
Sound Propagation ◽  
Vocal Tract ◽  
Vocal Folds ◽  
Equation Model ◽  
Voice Production ◽  
Human Voice ◽  
Large Eddy ◽  
Aeroacoustic Simulation ◽  
Scale Turbulence ◽  
The One

In an aeroacoustic simulation of human voice production, the effect of the sub-grid scale (SGS) model on the acoustic spectrum was investigated. In the first step, incompressible airflow in a 3D model of larynx with vocal folds undergoing prescribed two-degree-of-freedom oscillation was simulated by laminar and Large-Eddy Simulations (LES), using the One-Equation and Wall-Adaptive Local-Eddy (WALE) SGS models. Second, the aeroacoustic sources and the sound propagation in a domain composed of the larynx and vocal tract were computed by the Perturbed Convective Wave Equation (PCWE) for vowels [u:] and [i:]. The results show that the SGS model has a significant impact not only on the flow field, but also on the spectrum of the sound sampled 1 cm downstream of the lips. With the WALE model, which is known to handle the near-wall and high-shear regions more precisely, the simulations predict significantly higher peak volumetric flow rates of air than those of the One-Equation model, only slightly lower than the laminar simulation. The usage of the WALE SGS model also results in higher sound pressure levels of the higher harmonic frequencies.

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 Aeroacoustic Sound Source Characterization of the Human Voice Production-Perturbed Convective Wave Equation

2021 ◽  
Vol 11 (6) ◽  
pp. 2614
Author(s):  
Stefan Schoder ◽  
Paul Maurerlehner ◽  
Andreas Wurzinger ◽  
Alexander Hauser ◽  
Sebastian Falk ◽  
...  
Keyword(s):  
Wave Equation ◽  
Time Derivative ◽  
Maximum Amplitude ◽  
Vocal Folds ◽  
Far Field ◽  
Source Characterization ◽  
Turbulent Structures ◽  
Sound Sources ◽  
Voice Production ◽  
Human Voice

The flow-induced sound sources of human voice production are investigated based on a validated voice model. This analysis is performed using a hybrid aeroacoustic workflow based on the perturbed convective wave equation. In the first step, the validated 3D incompressible turbulent flow simulation is computed by the finite volume method using STARCCM+. In a second step, the aeroacoustic sources are evaluated and studied in detail. The formulation of the sound sources is compared to the simplification (neglecting the convective sources) systematically using time-domain and Fourier-space analysis. Additionally, the wave equation is solved with the finite element solver openCFS to obtain the 3D sound field in the acoustic far-field. During the detailed effect analysis, the far-field sound spectra are compared quantitatively, and the flow-induced sound sources are visualized within the larynx. In this contribution, it is shown that the convective part of the sources dominates locally near the vocal folds (VFs) while the local time derivative of the incompressible pressure is distributed in the whole supra-glottal area. Although the maximum amplitude of the time derivative is lower, the integral contribution dominates the sound spectrum. As a by-product of the detailed perturbed convective wave equation source study, we show that the convective source term can be neglected since it only reduces the validation error by 0.6%. Neglecting the convective part reduces the algorithmic complexity of the aeroacoustic source computation of the perturbed convective wave equation and the stored flow data. From the source visualization, we learned how the VF motion transforms into specific characteristics of the aeroacoustic sources. We found that if the VFs are fully closing, the aeroacoustic source terms yield the highest dynamical range. If the VFs are not fully closing, VFs motion does not provide as much source energy to the flow-induced sound sources as in the case of a healthy voice. As a consequence of not fully closing VFs, the cyclic pulsating velocity jet is not cut off entirely and therefore turbulent structures are permanently present inside the supraglottal region. These turbulent structures increase the broadband component of the voice signal, which supports research results of previous studies regarding glottis closure and insufficient voice production.

scholarly journals Anatomical structures involved in non-human vocalization

2005 ◽  
Vol 40 ◽  
pp. 33-43
Author(s):  
Alban Gebler ◽  
Roland Frey
Keyword(s):  
Sound Production ◽  
Vocal Tract ◽  
Mammalian Species ◽  
Thyroid Cartilage ◽  
Vocal Folds ◽  
Anatomical Structures ◽  
Volume Increase ◽  
Human Voice ◽  
Acoustic Analyses ◽  
Mass Increase

In order to understand the functional morphology of the human voice producing system, we are in need of data on the vocal tract anatomy of other mammalian species. The larynges and vocal tracts of four species of Artiodactyla were investigated in combination with acoustic analyses of their respective calls. Different evolutionary specializations of laryngeal characters may lead to similar effects on sound production. In the investigated species, such specializations are: the elongation and mass increase of the vocal folds, the volume increase of the laryngeal vestibulum by an enlarged thyroid cartilage and the formation of laryngeal ventricles. Both the elongation of the vocal folds and the increase of the oscillating masses lower the fundamental frequency. The influence of an increased volume of the laryngeal vestibulum on sound production remains unclear. The anatomical and acoustic results are presented together with considerations about the habitats and the mating systems of the respective species.  

SIMULATIONS OF VOCAL FOLDS WITH AN ANALOG CIRCUIT

1999 ◽  
Vol 09 (06) ◽  
pp. 1075-1088 ◽  
Author(s):  
ROBERT REUTER ◽  
REINHOLD ORGLMEISTER ◽  
HANSPETER HERZEL
Keyword(s):  
Analog Circuit ◽  
Narrow Band ◽  
Phase Locking ◽  
Vocal Folds ◽  
Complex Signals ◽  
Voice Production ◽  
Voice Source ◽  
Human Voice ◽  
Return Maps ◽  
Left Right Asymmetry

The human voice source generates complex signals including subharmonics and toroidal oscillations. Essential features of voice production are covered by two-mass models where each vocal fold is represented by two oscillators. We present a related analog circuit which allows online analysis of the generated complex signals. Using narrow-band spectrograms various bifurcations due to left–right asymmetry are monitored. Time series, spectra, return maps, and response measurements provide further detailed information about phase-locking and toroidal oscillations. Finally, possible clinical applications are discussed.

A Quantitative Output-Cost Ratio in Voice Production

2001 ◽  
Vol 44 (1) ◽  
pp. 29-37 ◽  
Author(s):  
David A. Berry ◽  
Katherine Verdolini ◽  
Douglas W. Montequin ◽  
Markus M. Hess ◽  
Roger W. Chan ◽  
...  
Keyword(s):  
Vocal Tract ◽  
Human Subjects ◽  
Vocal Folds ◽  
Cost Ratio ◽  
Voice Production ◽  
Wide Range ◽  
Subglottal Pressure ◽  
Potential Clinical Utility ◽  
Acoustic Output ◽  
Excised Larynx

A quantitative output-cost ratio (OCR) is proposed for objective use in voice production and is defined as the ratio of the acoustic output intensity to the collision intensity of the vocal folds. Measurement of the OCR is demonstrated in a laboratory experiment using 5 excised larynges and a transducer designed for use on human subjects. Data were gathered at constant fundamental frequency (150 Hz). Subglottal pressure was varied from 1.0 to 1.6 kPa, and glottal width at the vocal processes was varied from a pressed condition to a 2-mm gap. The OCR was plotted as a function of glottal width. With no vocal tract, the excised larynx experiments yielded a broad maxima in the OCR curves, across all subglottal pressure conditions, at about 0.6 mm. Computer simulations indicate that sharper maxima may occur when the influence of the vocal tract is taken into account. The potential clinical utility of the OCR is discussed for treatment of a wide range of voice disorders, including those involving both hyper- and hypoadduction.

scholarly journals Voice and Voice Quality

Linguistics ◽  
2020 ◽  
Author(s):  
Jody Kreiman
Keyword(s):  
Mate Selection ◽  
Animal Species ◽  
Vocal Tract ◽  
Voice Quality ◽  
Vocal Folds ◽  
The Body ◽  
Voice Production ◽  
Biologically Relevant ◽  
Research Areas ◽  
Integral Role

The sound of a voice—its quality—plays an integral role in the biological and social existences of animal species ranging from frogs to birds to elephants to primates and humans. Across animal species, voice plays a part in many, many aspects of behavior, including mate selection and attraction, social organization, identification of parent/child/significant others, signaling of emotion and aggressive intent, and providing information about health, age, sex, and size. Voice quality is a critical component of acting, oratory, singing, motivating and persuading others, and projecting a likeable image across space (and of course is essential to the production of spoken language). The study of voice quality is thus by its very nature inherently interdisciplinary, to an extent that can create a large burden of scholarship on those wishing to understand not just what sounds occur, but why and how they carry the messages they do. The study of voice quality also depends critically on understanding voice production and acoustics. Biologically, a voice necessarily reflects the body that produced it—the size and shape of the vocal folds and vocal tract, patterns of articulation, and so on—and perception has co-evolved with those phonating bodies, so it functions as it does to take advantage of the information on offer about the speaker. In the same way, speakers produce sound in order to communicate with or influence listeners, so the voice production apparatus has evolved to produce sounds listeners can hear and evaluate, and to send biologically relevant messages. Because voice production and perception are inseparably intertwined in this way, this bibliography includes references describing voice production as well as voice perception. Beyond these fundamentals, the study of voice quality includes work on perception of personal attributes (identity, age, size, race, sex, and so on), expression and perception of emotion and personality, linguistic uses of changes in quality, and a host of other research areas. This bibliography provides representative and/or foundational studies in many of these areas, as an invitation and a gateway to further exploration.

scholarly journals The Effects of Reverse Knowledge Spillover on China’s Sustainable Development: Sustainable Development Indicators Based on Institutional Quality

2021 ◽  
Vol 13 (4) ◽  
pp. 1628
Author(s):  
Xiaoxu Dong ◽  
Cheon Yu ◽  
Yun Seop Hwang
Keyword(s):  
Sustainable Development ◽  
Emerging Economies ◽  
Institutional Quality ◽  
Knowledge Spillover ◽  
Simultaneous Equation ◽  
Equation Model ◽  
Environmental Aspects ◽  
Development Indicators ◽  
Developed Economies ◽  
The One

This study investigates how reverse knowledge spillover (RKS) generated through outward foreign direct investment (OFDI) promotes sustainable development in an investment home country. Economic, social, and environmental dimensions are the pillars of sustainable development and their indicators are developed upon the concept of institutional quality. To this end, we use a balanced panel of 30 Chinese Mainland provinces from 2003 to 2016 and employ a simultaneous equation model to analyze the data in order to observe the direct and indirect effects of OFDI-induced RKS on sustainable development. The current study adopts several indicators to capture the economic, social, and environmental aspects of sustainable development. Additionally, we classify RKS into two types, given the investment destinations in terms of developed economies and emerging economies. On the one hand, our findings confirm that OFDI-induced RKS from developed economies facilitates domestic innovation but negatively affects progress on social and environmental development. On the other hand, OFDI-induced RKS from emerging economies is not conducive to domestic innovation, but it directly fosters sustainable development.

scholarly journals Vibrations of Nonlinear Elastic Structure Excited by Compressible Flow

2021 ◽  
Vol 11 (11) ◽  
pp. 4748
Author(s):  
Monika Balázsová ◽  
Miloslav Feistauer ◽  
Jaromír Horáček ◽  
Adam Kosík
Keyword(s):  
Compressible Flow ◽  
Nonlinear Elasticity ◽  
Vocal Tract ◽  
Stokes Equations ◽  
Vocal Folds ◽  
Nonlinear Material ◽  
Navier Stokes ◽  
Arbitrary Lagrangian Eulerian ◽  
Navier Stokes Equations ◽  
Reliable Solution

This study deals with the development of an accurate, efficient and robust method for the numerical solution of the interaction of compressible flow and nonlinear dynamic elasticity. This problem requires the reliable solution of flow in time-dependent domains and the solution of deformations of elastic bodies formed by several materials with complicated geometry depending on time. In this paper, the fluid–structure interaction (FSI) problem is solved numerically by the space-time discontinuous Galerkin method (STDGM). In the case of compressible flow, we use the compressible Navier–Stokes equations formulated by the arbitrary Lagrangian–Eulerian (ALE) method. The elasticity problem uses the non-stationary formulation of the dynamic system using the St. Venant–Kirchhoff and neo-Hookean models. The STDGM for the nonlinear elasticity is tested on the Hron–Turek benchmark. The main novelty of the study is the numerical simulation of the nonlinear vocal fold vibrations excited by the compressible airflow coming from the trachea to the simplified model of the vocal tract. The computations show that the nonlinear elasticity model of the vocal folds is needed in order to obtain substantially higher accuracy of the computed vocal folds deformation than for the linear elasticity model. Moreover, the numerical simulations showed that the differences between the two considered nonlinear material models are very small.

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