NUMERICAL INVESTIGATION OF DRAG COEFFICIENTS OF 2-BUNDLED CONDUCTORS
Haijiang Xu 1*, Hongzhou Deng 1 and Xing Ma 2
1 Department of Structural Engineering, Tongji University, Shanghai, China
2 School of Natural and Built Environments, University of South Australia, Adelaide, Australia
Drag coefficients of 2-bundled conductors are investigated by numerical simulation. Parametric analysis of meshing scheme, Y+ and time step size are preliminarily conducted with a two-dimensional circular cylinder model. It is found that Y+ should be within 10~15 and time step size should be no larger than 1/250 of vortex shedding period in transient analysis. An elaborate model with the same aerodynamic shape of real conductors is proposed. Drag coefficients of 2-bundled conductors at varied along-wind and across-wind distances are obtained and compared with wind tunnel test results. In tandem arrangement, shielding effect exists at any distance, while in side-by-side arrangement, shielding effect can be ignored when distances are larger than 8 times conductor diameter. Drag coefficients of 2-bundled conductors are much smaller than specified values in codes. It is suggested that shielding effect should be considered in wind-resistance design of ultra-high voltage transmission lines.
Drag coefficient; 2-bundled conductors; Conductor model; Shielding effect