汽车高速风噪声传递特性及机理研究

In order to control automobile interior and exterior aerodynamic noise effectively, noise generation mechanism and transmission characteristics has to be investigated above all. In this project, basic aeroacoustic theory analysis, wind tunnel experiment, SEA analysis method and simulation is combined together closely to do the work. Through this method, a more accurate aero-vibro-acoustic coupling model would be established. At the meantime, based on the wave-number theory, the prediction accuracy of interior noise with SEA method could be raised by the meaning of better separation of wall pressure fluctuation and sound pressure components. In this way, flow induced noise generation and transmission mechanism could be better understood vice versa. Based on the research results, a complete CFD/SEA method could be formed to predict vehicle interior aerodynamic noise. . This research work involves some difficulties and hot points of interdisciple scientific problem between aerodynamics and acoustics. At the meantime, the research results could guide the CAE engineering work of wind noise prediction of automobile industry. So this research work has great value on theory and application engineering.

为了有效控制汽车高速风激励下的车内外气动噪声水平，必须首先研究车辆气动噪声产生的机理及传递特性。本课题应用气动声学基本理论分析、风洞试验、SEA分析和数值计算紧密交叉结合的方法开展研究，预期建立更准确的流体－振声耦合的分析模型。同时，基于波数理论更准确地分离流体的压力脉动及声场的声压波动分量来进一步提高SEA方法预测车内噪声的计算精度，从而更进一步准确地揭示流体及声作用的激励及传递机理。基于以上研究成果，可以形成完整的应用CFD/SEA方法进行车内气动噪声精确预测的方法。. 研究涉及到气动噪声难点和热点基础科学问题，是空气动力学和声学学科的交叉研究，同时对汽车工业界的风噪仿真分析具有重要的指导作用。因此研究结果具有重要的理论意义及现实的应用价值。

本项目针对汽车风噪研究及开发领域的关键科学问题及技术难点，应用理论分析、风洞试验及数值计算紧密结合的方法，系统研究了汽车高速风噪声产生及传递的特性及机理。探索出针对复杂几何型面的基于可压流体的压力脉动计算方法，并基于波数理论，应用MATLAB编程首次提出并实现了针对作用于不规则表面的流场及声场压力脉动的分离方法，籍此建立了精确的气-振-声耦合模型。研究成果很大程度地提高了在中高频段应用SEA方法对车内气动噪声进行预测的精度，揭示了两种压力脉动向车内传递的机理及效率，形成了完整的应用CFD/SEA方法进行车内气动噪声精确预测的方法。在低频段，针对流致振动及声辐射问题，也开发出了一套基于CFD/FEM的可靠的计算方法。研究成果可以直接指导并用于汽车行业风噪性能计算及开发。特别在汽车的早期设计阶段，就可以实现车身造型因素对车内气动噪声的可靠预测，一定程度上可缩短车型开发的周期，节约开发费用。