Numerical investigation of the fluid structure acoustics interaction on a simplified car model

Abstract

Part of vehicle interior noise is caused by the complex turbulent flow field behind the a-pillar and side mirror. It excites the structure of the side window, which radiates noise into the interior. Both aerodynamic pressure excitation and acoustic sound sources in the flow play an important role. In this work, the influence of both excitation mechanisms is investigated numerically in a hybrid simulation on a simplified car geometry. The generic model allows for an exact definition of boundary conditions and good reproducibility of simulation results. An incompressible Large-Eddy-Simulation (LES) of the flow is conducted, from which acoustic source terms within the flow field and transient fluid forces acting on the surface of the side window are extracted. This data is used in a coupled vibroacoustic and aeroacoustic simulation of the structure and passenger cabin of the vehicle. A finite element (FE) approach is used for the simulations and detailed modeling of the structure and the influence of interior absorption properties is emphasized. The computed excitation on the side window and the interior noise levels are successfully validated by using experimental data. The importance and contribution of both aerodynamic and acoustic pressure excitation to the interior sound level are determined.

The Role of Forebody Topology on Aerodynamics and Aeroacoustics Characteristics of Squareback Vehicles using Computational Aeroacoustics (CAA)

“…The latter category includes well-studied forebody topologies, such as the SAE T4 body (SB) [9,[23][24], extensively investigated for Aeroacoustics, and the Windsor body (WB) [36-38], which has recently gained attention as a test case geometry, particularly with broader research participation aimed at comprehending various numerical modelling approaches [39]. Both SB and WB exhibited clearly de ned but slightly exaggerated A-pillars, as shown in Fig.…”

“…To ensure robustness, the employed modelling methodology is extensively veri ed and validated against the available experimental results of Nusser et al [23], speci cally concerning the full-scale squareback SB geometry (detailed in Section 3). However, for other squareback geometries examined in this study, no corresponding experimental data or numerical results are available for comparison.…”

“…For instance, the interface between the A-pillar and mirror generates much of the high-frequency aeroacoustics energy radiated from the vehicle [9][10][11] in addition to altering the vehicle drag by ~ 13.3% [9]. Therefore, alongside the emphasis on aerodynamic drag reduction, there is a growing recognition of the importance of addressing the overall aeroacoustics signature of the vehicle [12][13][14][15][16].…”

“…Many studies have employed a range of experimental and numerical techniques to examine the mechanisms underlying wind-induced noise radiation. These studies have covered a wide spectrum of scenarios, ranging from isolated features such as generic half-round side-view mirrors [17][18][19][20][21] to standard squareback SAE-T4 geometries that incorporate simpli ed side-view mirror representations with both generic and modi ed A-pillars [11,22,23]. Investigations have also been conducted on SAE-T4 models without side-view mirrors but with an A-pillar [9,24], as well as with realistic mirrors [22,25,26].…”

Zonal direct-hybrid aeroacoustic simulation of trailing edge noise using a high-order discontinuous Galerkin spectral element method

“…Traditionally, in hybrid CAA of low Mach number cases, the acoustic sources are extracted from an incompressible flow simulation. For example, Nusser and Becker [10] use this approach to predict vehicle interior noise. In such a case, specific aeroacoustic effects like acoustic feedback cannot be predicted due to a neglected interaction of hydrodynamics and acoustics.…”