高速公路透风型挡风墙不同位置防风特性的数值模拟研究

A Computational Study of Wind-break Performance of Ventilated Wind-break Wall in Different Locations on the Highway

应用FLUENT软件对侧风影响下高速公路汽车运行时的气动特性进行了三维稳态数值模拟,研究了透风型挡风墙在不同位置时汽车气动侧向力系数、升力系数及倾覆力矩系数随横摆角变化的特征,并与不设挡风墙的流场特征进行了对比。结果表明,修筑透风型挡风墙能够有效地减弱侧风对小轿车的作用力;同一侧风状态下,透风型挡风墙的不同修筑位置对应不同的汽车的气动侧向力系数、升力系数及倾覆力矩系数。汽车运行速度为120km.h-1,横摆角为31.0°或36.9°时(侧风风速为20m.s-1和25m.s-1),透风型挡风墙最佳的修筑位置为距离路肩2.1m,此时的倾覆力矩系数最小;当横摆角为42.0°或46.4°时(侧风风速为30m.s-1和35m.s-1),透风型挡风墙的最佳修筑位置为距离路肩2.4m。

A CFD software FLUENT is used to perform the three-dimension steady numerical simulations of the aerodynamic properties of a car traveling on highway under cross-wind conditions.With the change of yaw angle β,the variation characteristics of the coefficients of aerodynamic forces and rollover moment acting on the car across the highway with a ventilated wind-break wall set in different locations have been studied.To compare with the wind-break performances of ventilated wind-break wall,the aerodynamic characteristics of the flow around the car without wind-break wall also have been calculated.Results show that the wind forces acting on the car reduce greatly with ventilated wind-break wall on the windward side of the highway.Coefficients of aerodynamic forces and rollover moment differ with regard to different locations of the ventilated wind-break wall.To achieve the minimum rollover moment coefficient,it is reasonable to build the ventilated wind-break wall 2.1 m away from the road shoulder when the car speed is held constant at 120 km·h-1 and the yaw angle is 31.0° or 36.9°（cross-wind at a speed of 20 m·s-1 or 25 m·s-1）.In turn,it will be 2.4 m away when the yaw angle changes to 42.0° or 46.4°（cross-wind at a speed of 30 m·s-1 or 35 m·s-1）.