Aerodynamic characteristics of high-speed trains on box bridges under turbulent skew winds

In this paper, the pressure distributions, aerodynamic force coefficients, buffeting force spectrum, spanwise correlation, and aerodynamic admittance functions for the middle vehicle of a Chinese Railway High-speed (CRH) train (named CRH2) and a China Railway (CR) train (named CR400) on a streamlined box girder in turbulence flow, respectively, at yaw angles (β) ranging from 30° to 90°, with a 15° interval, were analyzed using pressure measurement. The locations of the peaks of the mean and root mean square pressure coefficients at different wind yaw angles are relatively constant, mainly occurring at the windward roof and bottom corners of the trains. It is clearly observed that the CR400 train exhibits higher negative pressure near the separation points at the roof corner of windward surface. The absolute values of side force coefficients and moment coefficients of the stationary trains increase with β values. It has been proved that the results of side force coefficients and moment coefficients obtained based on the wind speed component vertical to the train axis under skew winds mainly depend on the normal wind speed component, but the wind speed component parallel to the train axis still has some effect on them. Furthermore, the side force spectra and span-wise correlation results of CRH2 and CR400 trains are basically similar. The aerodynamic admittance functions of the side force decreases with increasing wind yaw angle, and the result is slightly larger due to the larger cross-sectional height of the CR400 train compared to the CRH2 train.