Influence of environmental wind on fluctuation velocity of contact wire of high-speed railway

The air damping and pulsating wind aerodynamic load acting on the contact wire were respectively deduced based on the aerodynamic theory, and the aerodynamic term was added to correct the formula of fluctuation velocity of contact wire. Through the wind tunnel test and computational fluid dynamics(CFD), the aerodynamic drag coefficient under the transverse wind environment was obtained, and the variation rules of fluctuation velocity of contact wire under different air dampings were analyzed. Based on the AR model and the structural characteristics of catenary, the pulsating wind field of catenary with time and space correlation was established. The influences of pulsating wind speed and wind attack angle on the fluctuation velocity of contact wire were analyzed through the simulation. Research result shows that the air damping of contact wire caused by the static wind load is very small. When the average wind speed reaches 30 m·s^-1, the air damping acting on the contact wire is only 0.3, and the fluctuation velocity of contact wire is stable at about 549.1 km·h^-1. Therefore, the air damping will not have a great impact on the fluctuation velocity of contact wire. When the wind attack angle of incoming wind is 60°, and the average wind speed is no more than 10 m·s^-1, the standard deviation and difference between the maximum and the minimum fluctuation velocities of contact wire under the pulsating wind are less than 1 and 6 km·h^-1, respectively. In this case, the fluctuation velocity of contact wire has little change compared with the non-wind condition, and the influence of pulsating wind load on the fluctuation velocity of contact wire is not obvious. When the wind speed reaches 40 m·s^-1, the average fluctuation velocity of contact wire decreases by 39.39 km·h^-1 compared with the non-wind condition, and the standard deviation and difference between the maximum and the minimum fluctuation velocities reach 11.84 and 75.98 km·h^-1, respectively. At this point, the fluctuation velocity of contact wire decreases and oscillates sharply, and the minimum is as low as 474.16 km·h^-1. Therefore, the larger the wind speed is under the pulsating wind, the more significant the impact of pulsating wind load is on the fluctuation velocity of contact wire. When the wind speed is maintained at 30 m·s^-1, and the attack angle of incoming wind is 0°-30°, the standard deviation and difference between the maximum and the minimum fluctuation velocities are less than 1 and 5 km·h^-1, respectively. In this case, the pulsating wind load has little influence on the fluctuation velocity of contact wire. When the wind attack angle is 90°, the standard deviation and difference between the maximum and the minimum fluctuation velocities reach 12.38 and 73.19 km·h^-1, respectively. At this point, the fluctuation velocity of contact wire decreases and oscillates sharply, and the minimum is as low as 472.91 km·h^-1. Therefore, under the action of pulsating wind, the more the incoming wind tends to the horizontal direction, the less influence it has on the fluctuation velocity of contact wire.