Numerical Simulation Of Aerodynamic Parameters For Galloping Of Iced Conductor With Crescent Shape

In the condition of certain wind velocity, iced conductors with non-circular cross-section produce self-excited vibration. When the frequency of vibration is close to the intrinsic frequency of the conductors, it is prone to generate galloping, which is so called dancing. In the study of galloping, the prime concern is the aerodynamic parameters of the iced conductors in the air, and some experimental investigations have been done. However, because of the variability of ice shape, it is not practical to do wind-tunnel tests for every case due to its high cost. Therefore numerical simulation becomes a valuable choice. In this paper, by computing the flow around crescent iced conductor models, its aerodynamic characteristics are obtained. The applicability of numerical simulation method to predict galloping instead of wind tunnel test is investigated.According to the features of crescent iced conductor, two-dimensional numerical models of iced conductor are built using the FLUENT. Drag coefficients and lift coefficients of two different thickness of crescent iced model under the different wind speeds are calculated. The influence of wind speed and ice thickness on the aerodynamic characteristics is analyzed. The peak of lift coefficient's amplitude changing with different attack angles is investigated. The instability of crescent iced conductors by observing the negative aerodynamic damping of the conductors is to be predicted.Results in this paper show that the simulated results fit well with the wind test results. The ice thickness and wind speed are crucial to the system damping of the crescent iced conductors. The Den coefficient calculated from the numerical simulation can predict the traverse instability of the iced conductor in wind. The results in this paper provide a certain basis for galloping control of iced conductor.