Study on Aerodynamic Instability and Galloping Response of Rail Overhead Contact Line Based on Wind Tunnel Tests

The overhead contact line is a tensioned cable structure erected along the railroad to power the electric train. Under the wind load, the galloping of OCL caused by aerodynamic instability may form a large amplitude, which is a big potential threat to the normal operation of the electric railway. In this paper, a wind tunnel test is performed to investigate the aerodynamic coefficients of the contact line with two levels of wear. The aerodynamic instability of the contact line can be observed on a worn contact wire at around an 8° wind angle of attack. Employing a nonlinear finite element model of the OCL, the galloping is reproduced and analysed via several numerical simulations. The effect of the wear level and angle of attack on the galloping response is analysed. The galloping amplitude of the contact line spikes at the angle of attack of 8° and 9° at 20% and 30% wear levels, respectively. Then damping dropper is included in the model, and its effect on the suppression of the OCL galloping is quantified. The results indicate that a damping dropper of 100 Ns/m is recommended to be mounted on the railway OCL to reduce the detriment of galloping under a strong wind field.