The effect of moving train on the aerodynamic performances of train-bridge system with a crosswind

Abstract

Some aerodynamic results about the effect of moving train on the aerodynamics of train-bridge system in crosswinds are introduced using a computational fluid dynamics (CFD) method. In the simulation, a new overset mesh approach is applied to present the motion of trains, and the results are compared with that of the scaled wind tunnel experiment to validate the accuracy of the mesh and algorithm. Besides, the aerodynamic characteristics associated with the train and bridge are discussed for a range of resultant yaw angles. It is found that the resultant yaw angle is significantly important for the aerodynamic performances of trains, and the aerodynamic interaction on the nose of head-car can affect the flow features around train-bridge system to produce larger aerodynamic loads on the head-car. Furthermore, a new fitting formula for some resultant yaw angles is proposed to predict the aerodynamic forces on trains. Finally, the time-varying forces on the bridge are presented and a sudden change of aerodynamic loads is also observed due to the effect of moving train. The variation magnitude of forces depends on the train speed, and the mean value of forces is only determined by the natural wind velocity.