The Aerodynamic Characteristics And Running Safety Of High-speed Train Under Rain And Crosswind Conditions

With the rapid development of China high-speed railway and the continuous increase of the train speed, the train safety operation under the diversified climate conditions are become more and more complicated in different region and season. The train aerodynamic characteristics change in extreme weather working conditions, for example the crosswind, the rainstorm and so on. It is considerably concerned to study the aerodynamic characteristics and safe train operation of high-speed train under extreme weather conditions.Based on the steady-state incompressible Navier-Storkes equation, standard k-ε turbulence model, and Eulerian two-phase model, the aerodynamic performance of a high-speed train under rainstorm and strong crosswind conditions are modeled using the Eulerian two-phase model in this paper. The impact of heavy rainfall on train aerodynamics is investigated using commercial software FLUENT, coupling heavy rain and a strong crosswind. The lift and side forces increase with the cross wind speed. The drag force increases firstly and then decreases with the cross wind speed, reaching maximum at about15m/s. Results show that the lift force, side force, and rolling moment of the train increase significantly under rain conditions than no rain condition.Meanwhile, a quasi-static stability analysis using the moment balance is utilized to determine the limit safety speed of train under different rain and wind levels. Results show that the train is more easily to overturn on the inner curve track. The train limiting speeds under rain decrease about10%～15%than that of without rain, which means that the train is more easily to overturn under strong rain condition.