Improving Underbody Wind Noise Transmission of Electric Vehicles using Simulation

Interior noise at cruising conditions is important for all passenger vehicles. Excessive background noise levels can cause fatigue among passengers by forcing raised conversation levels. In addition, reduced accuracy of voice commands for infotainment systems can be annoying. At freeway cruising speeds, wind noise is a dominant source of interior noise, with a major portion of fluctuating pressure entering the cabin through underbody panels. While electric vehicles may be able to locate their battery packs so as to attenuate some of the underbody wind noise transmission, it is difficult to treat all underbody panels with equal effectiveness. In this study, underbody wind noise from a typical SUV-shaped vehicle is analyzed through simulation. Transient, compressible CFD using the Lattice-Boltzmann Method is coupled with a Statistical Energy Analysis structural acoustic vehicle model to predict panel contributions to interior wind noise. Sources of exterior flow noise are visualized to highlight key paths. Then strategies to distribute battery and sound package attenuation are demonstrated to control underbody wind noise transmission while constraining added mass that would reduce range.