## 4 Discussion and Conclusions  
Large Eddy Simulations of subsonic incompressible flow in a model of human larynx were realized. The effect of the SGS turbulence model on the flow field, namely the flow rate, velocity, pressure and vorticity was analyzed in three variants--the laminar (no SGS), One-Equation and WALE SGS model. Compared to the classical Smagorinsky algebraic SGS model, the One-Equation SGS model has two prominent features--it is more suitable for high Reynolds number flows and avoids the inaccurate assumption of local balance between SGS energy production and dissipation [57]. However, similar to the Smagorinsky model, the One-Equation model is known to over predict the turbulent viscosity in regions where shear is dominant, that is, in the boundary layer adjacent to the vocal folds and in the shear layers of the glottal jet. The WALE SGS model, on the contrary, produces zero eddy viscosity in cases of pure shear flow, and recovers the proper \(\gamma^{3}\) near-wall scaling for the eddy (turbulent) viscosity without requiring a dynamic procedure. Moreover, [PERSON] and [PERSON] [30] showed that it can handle laminar-turbulent transition, which makes it attractive for complex geometries and specifically for glottal flow simulations. In the results of the CFD simulations, the waveforms of the flow rate show that the peak flow rate simulated by the One-Equation and WALE SGS models is lower than in the laminar case by 16.76% and 5.26%, respectively. It is necessary to note that these values are obtained for airflow driven by constant transglottal pressure. Other studies commonly prescribe a less realistic constant inlet velocity condition, where this effect cannot be observed. In our simulations, the differences in the peak flow rate are clearly induced by the SGS model, which acts through the turbulent SGS viscosity adding to the molecular viscosity of air and helps to block the airflow in the narrowest constriction between the vocal folds. The results prove that the WALE model predicts considerably lower, and presumably more realistic, values, not localized in the shear layers. Due to the disparity of scales between the flow structures and acoustic wavelengths, a hybrid aeroacoustic approach based on the perturbed compressible wave equations was used. The flow results computed by the Finite Volume method were used to evaluate the aeroacoustic sources. These were interpolated from the fine grid covering the larynx to the coarse grid of the larynx and vocal tract, where the acoustic variables were computed by the finite element method. The visualization of the aeroacoustic sources in the frequency domain shows that the laminar and WALE models predict slightly stronger aeroacoustic sources compared to the One-Equation model. Sound sources at the fundamental frequency \(f_{0}\) are located primarily in the glottis. At higher harmonic frequencies, the sources are distributed also in the supraglottal vestibule and further downstream of the glottis, especially in the shear layer of the jet and in places, where the fast glottal jet interacts with the ventricular folds and with the slowly recirculating air in the supraglottal spaces. The acoustic spectra of the sound evaluated 1 cm from the lips show important differences between the simulations based on the laminar CFD data, and LES simulations with the One-Equation and WALE SGS models. The sound pressure levels from the WALE simulation are significantly higher than those from the One-Equation model, especially at frequencies above 1000 Hz, where the difference reaches up to 15 dB. In the case of the vowel [i:], the SPL predictions based on the WALE model exceed even those from the laminar model. This can be partly explained by the fact that the CFD simulations using the One-Equation model result in lower flow rates and pressure fluctuations.