一种新数值工具在车辆气动声学开发中的应用

Application of a Newly Implemented Numerical Tool for Aeroacoustic Vehicle Development

摘要:

为了优化车辆开发过程的有效性，数值气动声学分析法的实施和应用对汽车制造商来说变得越来越重要。提出了一种结合延迟分离涡流模拟和基于Lighthill方程及声学扰动方程的有限元模型混合数值工具，应用OpenFOAM和Actran软件实现了基于声学有限元法的近场声源区提取及声学压力脉动计算，并尝试应用于车顶扰流板及后视镜区域的气动噪声计算及分析。在兰博基尼Urus车型上，研究了不同车顶扰流板设计的气动声学行为，将仿真结果与斯图加特大学气动声学全尺寸风洞的实验结果进行比较，发现了令人信服的相关性。此外，探讨了扰流板上的主要噪声产生机制，研究了汽车表面压力波动水平随几何形状改变的变化情况。

Abstract:

Nowadays， the implementation and application of numerical methodologies for aeroacoustic analysis become increasingly essential for car manufacturers in order to optimize the effectiveness of the vehicle development process. In this paper， a hybrid numerical tool based on the combination of a delayed detached eddy simulation and a finite element model was presented. The finite element model in turn was based on Lighthill’s equation and acoustic perturbation equations. The computational fluid dynamics and the computational aeroacoustics were respectively performed by the software OpenFOAM and Actran. The aeroacoustic behavior of the SUV Lamborghini Urus using different roof spoiler designs was investigated. The numerical simulations were verified against the experimental measurements conducted in the aeroacoustics full scale wind tunnel of the University of Stuttgart operated by FKFS. Furthermore， the main noise generation mechanisms at the spoiler were discussed and the change of pressure fluctuation level on the car surface with respect to a geometry variation was investigated.