Study on aerodynamic characteristics and running safety of two high-speed trains passing each other under crosswinds based on computer simulation technologies

Abstract

With the continuously increased running speed of high-speed trains, aerodynamic problems become more and more obvious. Running safety of trains under crosswinds is a serious problem among numerous aerodynamic problems. Aiming at this problem, this paper combines computational fluid dynamics with multi-body dynamics to study aerodynamic characteristics and safety problems when the high-speed train is running under crosswinds. Based on fluid software FLUENT, this paper computes the flow field of two high-speed trains passing each other under crosswinds. Meanwhile, with combining the multi-body dynamic software SIMPACK with theories, the paper establishes a multi-body dynamic model of the high-speed train, and applies random aerodynamic loads which act on the high-speed train to this model. Impacts of aerodynamic forces (force moments) on aerodynamic characteristics and running safety of each train compartment in the open air are analyzed. Analyzed results show that: when two high-speed trains are passing each other at the same speed of 350 km/h and the crosswind speed is 15 m/s, maximum pressure fluctuations are at observation points near the lateral windows of the head train; aerodynamic forces and force moments of the head train are more than those of the mid-train and tail-train; the high-speed train still has a high safety performance under crosswinds, where the maximum derailment coefficient is 1.9, the reduction rate of the wheel load is 1.1 and the overturning coefficient is 0.98, all of which are smaller than the limit value. More comprehensive factors are considered by the computational model in this paper. It can be used as an effective method to study and evaluate the performance of two high-speed trains passing each other under crosswinds.