Investigation of Turbulent Wind Characteristics on Vehicles by Large Eddy Simulation 2022-01-5047

Automotive aerodynamic development requires not only to reduce aerodynamic drag but also to develop vehicles that perform well under real road conditions. Although a few types of research have studied the wind characteristics vehicles experienced on-road, the mechanisms of turbulent effects on vehicle aerodynamics are still not well understood. For this reason, an alternative computational fluid dynamics (CFD) method is adopted in this study to reproduce the turbulent wind characteristics, with the aim of providing a more accurate and reliable simulation method to help further understand the wind environment in the atmospheric boundary layer. To fully trust this numerical method, both scale and full-scale simulations are conducted and verified with the corresponding data measured in wind tunnel experiments and on-road measurements. Results in this study indicate that the adopted CFD method can generate the turbulent wind properties in terms of turbulence intensity and turbulence length scale well, but there are some obvious differences in the standard deviation of velocity fluctuations and flow angle fluctuations as compared to wind tunnel experiments and on-road measurements, and these differences are considered to be acceptable in engineering applications. Particularly, characteristics of turbulent wind are obviously different from that of the uniform wind with respect to the velocity fluctuation, flow angle fluctuation, turbulence intensity, etc. Thus, if vehicles are expected to perform well on real roads, turbulent wind characteristics need to be considered in the aerodynamic design.