Buffeting Forces on Static Trains on a Truss Girder in Turbulent Crosswinds

Experiments were conducted in a wind tunnel with scaled models to investigate the aerodynamic characteristics of a train on a steel truss girder. Simultaneous surface pressure measurements were conducted under two turbulent flow fields. The aerodynamic-force coefficients, aerodynamic-admittance functions, and spanwise correlation characteristics of buffeting forces on the train were examined. A mean pressure coefficient suction peak was observed at the windward roof corner, and a fairly uniform pressure distribution was observed on the leeward surface of the train. The variation of the wind angle of attack (-3° to 3°) and turbulent flow field had minimal effects on the spanwise correlation of buffeting forces, whereas the effects of the train position on the truss girder and spanwise distance were significant. The aerodynamic admittances of the train were found to be a function of the train position on the truss girder and turbulent flow field. The effect of the wind angle of attack (-3° to 3°) on the aerodynamic admittances of the lateral and lift forces was mainly in the low-frequency region. Finally, empirical expressions were proposed to facilitate engineering applications.