Optimization research on aerodynamic figure of the box car under cross wind

Under cross wind, the aerodynamic performance of box car is the worst one in all the universal vehicles used in the railroad. Based on 2D steady and incompressible Navier-Stokes equation and k-ε turbulent model, using P64 Box Car as the prototype to analyze and compare the aerodynamic performance of cars with different roof figure by finite volume method, when these cars were under the cross wind of the same velocity. The results show that the figure of car roof greatly affects the aerodynamic performance of box car. The aerodynamic performance of arc-shaped roof cars is much better than that of prototype car with triangular roof, and the overturning moment is least when the roof arc radius is between 1600mm and 1800mm. Meanwhile, the angle of car roof effect the aerodynamic performance greatly too, and the overturning moment is least when the roof angle a changing from 140° to 144°.