A numerical study of the aerodynamic characteristics of ice-accreted transmission lines

Aerodynamic coefficients of single and 4-bundled ice-accreted conductors are investigated using the LES turbulence model and compared with the results of the wind tunnel test. Single conductors with span lengths of L = 1D and 10D are simulated, and the predicted aerodynamic coefficients with a span length of L = 10D show good agreement with the measured those within the estimated error range of the wind tunnel test, where D is the diameter of the single conductor. A systematic error estimation using the models with L = 2D, 3D, and 6D is conducted; the results show that a span length of L = 10D is long enough to predict aerodynamic coefficients. The effect of the accreted ice height, H, on the aerodynamic coefficients is investigated. It is found that negative pressure at the lower face near the leading edge significantly affects CL and CM and leads to the maximum absolute values of CL and CM at 12° for the conductor with H = 1D and at 16° for the conductor with H = 0.5D. The wake effect of 4-bundled conductors is also investigated by the analysis of the aerodynamic coefficients and the pressure distribution for each conductor. The wake of the windward conductors has a significant impact on CL and CM. Correction coefficients for leeward conductors are proposed to account for the wake effect, and the results show good agreement with the predicted aerodynamic coefficients of the 4-bundled conductors.