Hybrid aeroacoustic approach for the efficient numerical simulation of human phonation

Abstract

A hybrid aeroacoustic approach was developed for the efficient numerical computation of human phonation. In the first step, an incompressible flow simulation on a three-dimensional (3 D) computational grid, which is capable of resolving all relevant turbulent scales, is performed using STARCCM+ and finite volume method. In the second step, the acoustic source terms on the flow grid are computed and a conservative interpolation to the acoustic grid is performed. Finally, the perturbed convective wave equation is solved to obtain the acoustic field in 3 D with the finite element solver CFS++. Thereby, the conservative transformation of the acoustic sources from the flow grid to the acoustic grid is a key step to allow coarse acoustic grids without reducing accuracy. For this transformation, two different interpolation strategies are compared and grid convergence is assessed. Overall, 16 simulation setups are compared. The initial (267 000 degrees of freedom) and the optimized (21 265 degrees of freedom) simulation setup were validated by measurements of a synthetic larynx model. To conclude, the total computational time of the acoustic simulation is reduced by 95% compared to the initial simulation setup without a significant reduction of accuracy, being 7%, in the frequency range of interest.

3D-FV-FE Aeroacoustic Larynx Model for Investigation of Functional Based Voice Disorders

“…Characteristic parameters of the silicone model performance and corresponding physiological male values are shown in Table 1. Validation parameters in detail were: (1) Flow dynamic properties as pressure measurements and the velocity field with the glottal jet in the supraglottal region using particle image velocimetry (PIV) by Sadeghi et al (2018Sadeghi et al ( , 2019a, and (2) the acoustic signal by Schoder et al (2020). In this study, the investigated configurations of glottal insufficiency and asymmetric vocal fold oscillations are synthetic cases that were derived as combination from ex vivo (Birk et al, 2016(Birk et al, , 2017a and silicone model experiments (Kniesburges et al, 2013).…”

“…The aeroacoustic sound generation and acoustic wave propagation is described by the perturbed convective wave equation (PCWE) (Kaltenbacher et al, 2016), which is solved via the finite element solver CFS++ (Schoder et al, 2020). To compute the acoustic source term for the PCWE, the incompressible pressure field from the CFD is transferred onto the CAA mesh by a conservative interpolation scheme based on a cut cell algorithm (Schoder et al, 2019(Schoder et al, , 2020. The acoustic source term is then computed on the CAA grid as the partial time derivative of the incompressible pressure.…”

“…For the development of our hybrid (sound propagation is calculated based on aeroacoustic source terms from the flow simulation) 3D aeroacoustic numeric larynx model simVoice (Sadeghi et al, 2018(Sadeghi et al, , 2019aSchoder et al, 2020) for future clinic usefulness, it is essential to replicate normal and disordered glottal closures and dynamical asymmetries. A method to set up a workflow containing the import of various physiological and disordered glottal geometries into simVoice is shown in this study.…”

“…Numeric simulations, regarding the effect of the glottal insufficiency on the human voice, were done by Zörner et al (2016) and on the asymmetric vocal fold oscillations by Xue et al (2010) and Samlan et al (2014). In contrast to experimental models, computer models provide the complete 3D data of the flow field TABLE 1 | Parameter reported for normal male phonation in in vivo and ex vivo studies compared with the experimental silicone model synthVOICE (Kniesburges et al, 2013(Kniesburges et al, , 2016(Kniesburges et al, , 2020Kniesburges, 2014) (validation cases) and the performed numerical validation simulations by simVoice (Sadeghi et al, 2018(Sadeghi et al, , 2019aSadeghi, 2019;Schoder et al, 2020).…”

Hybrid Aeroacoustic Computations: State of Art and New Achievements

“…PCWE has been applied to HVAC systems 181,182 extensively. The prediction of fan noise 42,60,183,184 as well as human phonation 185,186 suits the assumptions of this equation.…”