Influence of Three-Dimensional Distortion on the Unsteady Lateral Force of a Train on a Streamlined Deck under Crosswinds

This study aims to investigate the influence of turbulent three-dimensional (3D) and distortion effects on the unsteady lateral buffeting force of trains on a streamlined deck and propose a closed form equation for the 3D aerodynamic admittance function (AAF). Six fluctuating wind fields were simulated to analyze the influences of different turbulence characteristics on the lateral force of trains through pressure measurement tests. In addition to a train on a bridge, a plain ground scenario was simulated as a reference. The results show that the lateral force correlation of the train is always greater than that of the fluctuating wind. As L-u/D increases, the lateral force coefficient and spanwise correlation of the lateral force increase, and the 3D effect weakens. The AAF is sensitive to L-u/D at high frequencies, and the wind exhibits a clear distortion effect during turbulence flow on the train. A difference exists between the aerodynamic characteristics of trains on the ground and on a bridge. The turbulence intensity has little influence on the lateral aerodynamic characteristics of a train. To correct the uncertainty caused by the 3D and distortion effects, a generalized AAF model was proposed to accurately estimate the gust loading on a train.