## 1 Introduction
Using an arbitrary Lagrangian-Eulerian description for the convective differential operators  
\[\frac{D}{Dt}=\frac{\partial}{\partial t}+\left(\mathbf{\bar{v}}-\mathbf{v}_{\rm rg} \right)\cdot\
abla\,, \tag{4}\]  
where \(\mathbf{v}_{\rm rg}\) is the relative velocity of the grid, we arrive at the PCWE for moving meshes [16]:  
\[\frac{1}{c^{2}}\ \frac{D^{2}\mathbf{v}^{\rm a}}{Dt^{2}}-\Delta\mathbf{v}^{\rm a}=-\frac{1}{ \bar{\rho}c^{2}}\left(\frac{\partial p^{\rm ic}}{\partial t}+\underbrace{ \left(\mathbf{\bar{v}}-\mathbf{v}_{\rm rg}\right)\cdot\
abla p^{\rm ic}}_{\text{ convective source term}}\right)\,. \tag{5}\]The formulation reduces the number of equation unknowns (acoustic pressure \(p^{\rm a}=\bar{\rho}\frac{D\psi^{\rm a}}{Dt}\) and particle velocity \(\mathbf{v}^{\rm a}=-\
abla\psi^{\rm a}\)) to just one scalar unknown, being the acoustic velocity potential \(\psi^{\rm a}\). Compared to the acoustic perturbation equation (APE) [13], the PCWE has two advantages. Firstly, it is a scalar equation and thus computationally efficient. Secondly, it describes aeroacoustics generated by incompressible flow structures and wave propagation through moving media [17]. Regarding the computational efficiency and the applicability to complicated geometries, the model was validated for the voice production process [18]. At low Mach numbers without back-coupling of the acoustic waves on the flow field, the numerical separation of flow and acoustics (hybrid aeroacoustic approach) is valid. This approach involves three steps (see Figure 1): (1) perform unsteady incompressible flow simulation; (2) compute the acoustic sources from the flow field; (3) simulate the sound propagation. In addition to the efficient model, these three steps guarantee a practical method for fast and accurate aeroacoustic computations regarding the physical assumptions and numerical requirements [19; 20; 21]. This hybrid aeroacoustic workflow was frequently applied to compute the human voice production [6; 9; 10; 22; 23; 24; 25; 26; 27; 28; 29; 30]. A full fluid-solid-acoustic coupling was presented by [24], who used [PERSON]'s acoustic analogy to calculate the acoustics. Recently, [PERSON]. [31; 32] developed a model to compute flow-induced sound and include vibration of the human vocal folds. This model coupled the immersed boundary method for incompressible flow to a finite element solver. The finite element solver computes the viscoelastic tissue and the linearized perturbed compressible equations [14]. However, the fully coupled fluid-structure simulations suffer from a lack of precise geometrical and material properties of the living tissues [24; 31]. Since the parameters are highly subject-specific and most of the vocal fold tissue measurements are still hardly applicable in-vivo to precisely determine the vocal fold material parameters [33; 34]. As shown in [35], the full fluid-structure interaction solution can be approximated properly by prescribing the vocal fold motion for the flow computation. In this way, the fluid-structure interaction is circumvented and spares considerable computational resources. According to these findings, [PERSON]. [18] describes a validated aeroacoustic model based on a simplified PCWE formulation in conjunction with the hybrid workflow. The larynx geometry of the numerical model is based on the experimental model of [36]. Firstly, the 3D flow inside the larynx is computed by an incompressible Large Eddy Simulation in combination with the wall-adapting local eddy-viscosity subgrid-scale model and a finite-volume cell-centered non-staggered grid. The vocal fold motion is enforced by the model of [37; 38]. Based on the experiments [39; 40], a constant inlet flow pressure of 2450 Pa and an outlet boundary flow pressure of 0 Pa was set. The wall boundaries are defined as no-slip, no-injection boundary conditions. Secondly, the acoustic source terms are computed on the flow grid and a conservative interpolation to the acoustic grid is performed [41].