A Stabilized Finite Element Method for the Mixed Wave Equation in an ALE Framework With Application to Diphthong Production

Guasch, Oriol; Arnela, Marc; Codina, Ramon; Espinoza, Hector

doi:10.3813/aaa.918927

Cited by 28 publications

(72 citation statements)

References 39 publications

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“…This physical phenomenon can be described by the mixed wave equation for the acoustic pressure p(x, t) and acoustic particle velocity u(x, t), expressed in an ALE (Arbitrary Lagrangian-Eulerian) frame of reference to account for the vocal tract movement [3]. The equation reads 1 ρ0c…”

Section: Acoustic Modelmentioning

confidence: 99%

“…In particular, a subgrid scale strategy was followed to avoid numerical instabilities when using the same interpolation for the acoustic pressure and the acoustic particle velocity. Details of the numerical implementation can be found in [3]. In the simulations the speed of sound was set to c0 = 350 m/s and the wall impedance to Zw = 83666 kg/m 2 s [22].…”

Section: Acoustic Modelmentioning

confidence: 99%

“…However, to reduce the complexity in simulations, these often make simplifications, such as synthesizing sound by interpolation of the area functions [1], two-dimensional vocal tracts [2] or 3D tubular vocal tracts [3,4], of the constituent phonemes. When using area functions, one assumes plane wave propagation, which is only accurate for frequencies below 4-5 kHz [5].…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of VV Utterances from Muscle Activation to Sound with a 3D Model

et al. 2017

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We propose a method to automatically generate deformable 3D vocal tract geometries from the surrounding structures in a biomechanical model. This allows us to couple 3D biomechanics and acoustics simulations. The basis of the simulations is muscle activation trajectories in the biomechanical model, which move the articulators to the desired articulatory positions. The muscle activation trajectories for a vowel-vowel utterance are here defined through interpolation between the determined activations of the start and end vowel. The resulting articulatory trajectories of flesh points on the tongue surface and jaw are similar to corresponding trajectories measured using Electromagnetic Articulography, hence corroborating the validity of interpolating muscle activation. At each time step in the articulatory transition, a 3D vocal tract tube is created through a cavity extraction method based on first slicing the geometry of the articulators with a semi-polar grid to extract the vocal tract contour in each plane and then reconstructing the vocal tract through a smoothed 3D mesh-generation using the extracted contours. A finite element method applied to these changing 3D geometries simulates the acoustic wave propagation. We present the resulting acoustic pressure changes on the vocal tract boundary and the formant transitions for the utterance [Ai].

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Section: Acoustic Modelmentioning

confidence: 99%

Section: Acoustic Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis of VV Utterances from Muscle Activation to Sound with a 3D Model

et al. 2017

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“…An immersed boundary method is adopted in those works and contact is enforced by a kinematic constraint. With regard to VT acoustics, several works have been performed to date for static vowels sounds (see e.g., [6,7,8,9, 10]), and not long ago for dynamic vowel sounds as well [11].…”

Section: Introductionmentioning

confidence: 99%

“…At each time step of the computation an FSI problem is solved for the self oscillations and contact of the VF, following the strategy in [15]. Then a source term is computed and used as an inhomogeneous volume source for the wave equation in mixed form, in an arbitrary Lagrangian-Eulerian (ALE) frame of reference [11]. The implemented acoustic analogy may be viewed as a simplification of the acoustic perturbation equations for negligible convection velocity [16,17,18], which filters pseudo-sound to some extent.…”

Section: Introductionmentioning

confidence: 99%

A Unified Numerical Simulation of Vowel Production That Comprises Phonation and the Emitted Sound

Degirmenci¹,

Jansson²,

Hoffman³

et al. 2017

Interspeech 2017

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A unified approach for the numerical simulation of vowels is presented, which accounts for the self-oscillations of the vocal folds including contact, the generation of acoustic waves and their propagation through the vocal tract, and the sound emission outwards the mouth. A monolithic incompressible fluid-structure interaction model is used to simulate the interaction between the glottal jet and the vocal folds, whereas the contact model is addressed by means of a level set application of the Eikonal equation. The coupling with acoustics is done through an acoustic analogy stemming from a simplification of the acoustic perturbation equations. This coupling is one-way in the sense that there is no feedback from the acoustics to the flow and mechanical fields.All the involved equations are solved together at each time step and in a single computational run, using the finite element method (FEM). As an application, the production of vowel [i] has been addressed. Despite the complexity of all physical phenomena to be simulated simultaneously, which requires resorting to massively parallel computing, the formant locations of vowel [i] have been well recovered.

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Computational aeroacoustics to identify sound sources in the generation of sibilant /s/

Pont

Guasch

Baiges

et al. 2018

Numer Methods Biomed Eng

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A sibilant fricative /s/ is generated when the turbulent jet in the narrow channel between the tongue blade and the hard palate is deflected downwards through the space between the upper and lower incisors and then impinges the space between the lower incisors and the lower lip. The flow eddies in that region become a source of direct aerodynamic sound, which is also diffracted by the speech articulators and radiated outwards. The numerical simulation of these phenomena is complex. The spectrum of an /s/ typically peaks between 4 and 10 kHz, which implies that very fine computational meshes are needed to capture the eddies producing such high frequencies. In this work, a large-scale computation of the aeroacoustics of /s/ has been performed for a realistic vocal tract geometry, resorting to two different acoustic analogies. A stabilized finite element method that acts as a large eddy simulation model has been adopted to solve the flow dynamics. Also, a numerical strategy has been implemented that allows the determination, in a single computational run, of the separate contribution of the sound diffracted by the upper incisors from the overall radiated sound. Results are presented for points located close to the lip opening showing the relative influence of the upper teeth depending on frequency.

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A Stabilized Finite Element Method for the Mixed Wave Equation in an ALE Framework With Application to Diphthong Production

Cited by 28 publications

References 39 publications

Synthesis of VV Utterances from Muscle Activation to Sound with a 3D Model

Synthesis of VV Utterances from Muscle Activation to Sound with a 3D Model

A Unified Numerical Simulation of Vowel Production That Comprises Phonation and the Emitted Sound

Computational aeroacoustics to identify sound sources in the generation of sibilant /s/

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