Study on Radiated Noise of a Panel under Fluctuating Surface Pressure Due to an Idealized Side Mirror

Abstract

As traditional automobiles develop towards new energy vehicles, the noise, vibration and harshness (NVH) performance of automobiles is facing new challenges. Without the cover of the traditional engine noise and inlet and exhaust noise, the high-speed wind noise becomes more prominent. Thus, research on the calculation method of vehicle interior noise in high-speed driving condition is needed. However, vehicle body structure is complex, and the external excitation components are complicated. In order to analyze the method of predicting the vehicle interior noise at high speed, an idealized side mirror model is taken as the research object in this paper and the radiated noise of a panel under the fluctuating surface pressure (FSP) due to the idealized side mirror is studied. The FSP of the panel is first studied by the numerical simulations of incompressible and compressible flow field. For the incompressible flow field, the Corcos turbulent boundary layer (TBL) model is established to simulate the convective component and the boundary element method (BEM) is used to extract the acoustic component. Subsequently, the Corcos model coupling BEM method, the random modal force coupling BEM method and the deterministic modal force coupling BEM method are used separately to calculate the noise of the panel under the FSP. For the compressible flow field, the convective and acoustic component in the fluctuating pressure are separated by the wavenumber-frequency spectrum (WFS) method. The radiated noise of the panel under the FSP is calculated again by using the WFS, the method of random modal force and the method of deterministic modal force, respectively. Then, the computational time of the six methods of incompressible and compressible calculation is compared. Finally, a fast and accurate method of calculating the panel radiated noise under FSP is obtained by comparing the computational accuracy with the experimental results and combining the computational time: the method of incompressible random modal force. This method can be used to quickly and accurately analyze the vehicle interior noise at high speed, and to optimize the exterior protrusions and the vehicle sound package for improving the vehicle NVH performance at high speed.Appl. Sci. 2020, 10, 994 2 of 22 component of the outflow field in [2][3][4]. In order to analyze the effect of the acoustic component on the interior noise SPL of the vehicle, the characteristics of the acoustic component were studied. The researches show: both the convective and acoustic component are equally important contributors for the noise transmission to the vehicle cabin although the TBL pressure is 25 to 35 dB higher in level than that of the corresponding acoustic component [1].There are many kinds methods for calculating the response under the TBL excitation. One of the models for the TBL is presented by Corcos [5]. Then, Chase and Efimstov built models derived from Corcos expression, which can improve the predictions for the low-frequency range [4,6]. Birgersson et al. [7] used ...