Aero-Vibro-Acoustic Wind Noise-Simulation Based on the Flow around a Car

Becker, Stefan; Nusser, Katrin; Oswald, Marco

doi:10.4271/2016-01-1804

Cited by 4 publications

(3 citation statements)

References 27 publications

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“…To account for turbulence in the flow, a large eddy simulation (LES) with a Smagorinsky subgrid-scale model is used. It was shown in previous work [18,19] that this turbulence modeling approach is best suited to capture the small turbulent structures which occur around the simplified car model. In the acoustic regions, the propagation of sound is calculated based on the perturbed convective wave equation (PCWE) [20][21][22]:…”

Section: Methodsmentioning

confidence: 99%

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

Nusser

Becker

2021

Acta Acust.

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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.

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Section: Methodsmentioning

confidence: 99%

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

Nusser

Becker

2021

Acta Acust.

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“…9 The flow past the vehicle A-pillar is highly turbulent, and the position of the side view mirror in this region makes the mirror a significant contributor to wind noise generated. 10 Analysis of the side view mirror is critical in designing quieter interior cabins by taking into account factors such as the shape of the mirror, the alignment of the mirror to the side window and additional design features such as turn signals and rain gutters that are changed continuously due to aesthetic merits and to avoid any tonal noise characteristics. 11 Nevertheless, by examining generic mirror configurations, a deeper understanding of the flow and emitted noise generation can be gained and offer a high degree of repeatability.…”

Section: Introductionmentioning

confidence: 99%

Noise emitted from a generic side-view mirror with different aspect ratios and inclinations

2021

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Noise radiated from flow past different configurations of the Half-Round Mirror (HRM) mounted on a plate has been investigated using computational aeroacoustics (CAA).The Stress-Blended Eddy Simulation (SBES), together with the Ffowcs Williams-Hawkings (FW-H) acoustic analogy, was employed to predict near field flow and far-field noise, respectively. The numerical methodology was verified and validated for the standard HRM case against several previously published numerical and experimental data sets, which provides good agreement. Further, (i) the choice of different type of grids for CAA and (ii) the applicability of methods such as the Kirchhoff integral and the FW-H using near field inputs computed from the SBES were assessed. As a next step, the effect of induced noise from the HRM for different a) Aspect Ratios (AR) ranging from 1 to 2.5 and b) inclination of the mirror towards the plate (θ) ranging from 0° to 32° were investigated. For all the investigated cases, the distribution of the radiated noise exhibits a dipole-like structure closer to the plate and a monopole-like structure away from the plate. By inclining the mirror closer to the mounting plate, the emitted noise is reduced both in the vertical and lateral directions of the wake, whereas an increase in the AR of the mirror increases the induced noise considerably. The findings from the current study can provide a deeper understanding for effectively mitigating the induced aerodynamic noise from side-view mirrors.

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“…The RANS models are proved accurate enough to simulate the stationary aerodynamic characteristics in industrial applications (Heft et al , 2012a). In recent years, computational aerodynamics has been rapidly developed with the help of computer science and researchers are able to pay more attention to the transient flow cases, such as vehicle aero-acoustics (Becker et al , 2016; Ghasemian and Nejat, 2015), a couple of aerodynamic with vehicle’s motion (Huang et al , 2017; Huang et al , 2019; Li et al , 2018) and the understanding of the unsteady-state flow structures(Evstafyeva et al , 2017; Lucas et al , 2017; Östh et al , 2014). Unfortunately, the RANS models are weak in capturing the unsteady flow structures in transient simulations while the large eddy simulation (LES) method has been widely used in the transient flow field research (Krajnović, 2016; Minguez et al , 2008).…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis for wake flow field of Ahmed model based on a nonlinear-LRN/DES turbulence model

Zheng

Yang

Qiang

et al. 2021

HFF

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Purpose This paper aims to propose a precise turbulence model for automobile aerodynamics simulation, which can predict flow separation and reattachment phenomena more accurately. Design/methodology/approach As the results of wake flow simulation with commonly used turbulence models are unsatisfactory, by introducing a nonlinear Reynolds stress term and combining the detached Eddy simulation (DES) model, this paper proposes a nonlinear-low-Reynolds number (LRN)/DES turbulence model. The turbulence model is verified in a backward-facing step case and applied in the flow field analysis of the Ahmed model. Several widely applied turbulence models are compared with the nonlinear-LRN/DES model and the experimental data of the above cases. Findings Compared with the experimental data and several turbulence models, the nonlinear-LRN/DES model gives better agreement with the experiment and can predict the automobile wake flow structures and aerodynamic characteristics more accurately. Research limitations/implications The nonlinear-LRN/DES model proposed in this paper suffers from separation delays when simulating the separation flows above the rear slant of the Ahmed body. Therefore, more factors need to be considered to further improve the accuracy of the model. Practical implications This paper proposes a turbulence model that can more accurately simulate the wake flow field structure of automobiles, which is valuable for improving the calculation accuracy of the aerodynamic characteristics of automobiles. Originality/value Based on the nonlinear eddy viscosity method and the scale resolved simulation, a nonlinear-LRN/DES turbulence model including the nonlinear Reynolds stress terms for separation and reattachment prediction, as well as the wake vortex structure prediction is first proposed.

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Aero-Vibro-Acoustic Wind Noise-Simulation Based on the Flow around a Car

Cited by 4 publications

References 27 publications

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

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

Noise emitted from a generic side-view mirror with different aspect ratios and inclinations

Numerical analysis for wake flow field of Ahmed model based on a nonlinear-LRN/DES turbulence model

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