Numerical Simulations on Aerodynamic Forces of Circular Steel Tubular Lattice Structures

Abstract

Due to the high flexibility, light self-weight and low damping ratio of the power transmission tower, wind loads are the dominant lateral loads at its design stage. This study conducted a series of rigid model tests on the aerodynamic forces of circular steel tubular lattice structures under smoothly uniform flow conditions in the wind tunnel laboratory, and the models were fabricated based on a super high-rise power transmission tower in Huainan-Nanjing-Shanghai UHVAC transmission line. The Large-eddy simulation（LES） of lattice structures were performed to simulate the aerodynamic forces in the longitudinal, transverse and lateral directions, and the results were compared to the corresponding specifications in the available wind codes or standards. In addition, the aerodynamic forces of lattice structures were simulated by using LES under the flow conditions with turbulence intensities of 5%, 10%, 15% and 20%. The results showed that the numerical results were in relatively reasonable agreement with the experimental measurements, and the incoming turbulence intensity had indispensable influences on the fluctuating components of the aerodynamic forces. Moreover, the maximum positive pressures were observed on the windward surface at the junction of the strut and the diagonal member, while the maximum negative pressures were recorded on the lateral surface of the strut. Furthermore, the vorticity analysis showed that the vorticity in the x-direction was more scattered while those in the y- and z- directions were more uniform and continuous. The findings of this study are of great use for evaluating the aerodynamic forces of circular steel tubular lattice structures in the practice constructions.

Keywords: lattice towers,  LES,  aerodynamic force,  transmission towers