Wind-induced Vibration Characteristics of Cable-free Antenna Mast Based on Bidirectional Fluid-structure Interaction
A numerical simulation based on bidirectional fluid-structure interaction is carried out to study the wind-induced vibration characteristics of regular hexagonal cable-free antenna mast.In this paper,we established a three-dimensional finite element model of the solid mesh and external flow field overlapping mesh of the cable-free antenna mast.ANSYS Workbench is used to build a bidirectional fluid-structure interaction simulation system based on Transient,Fluent and System Coupling.The simulation system is used to analyze the lateral and downwind vibration displacement and force of the mast at different wind speeds,and the natural frequencies of the first six orders of the mast and their corresponding modes are calculated by using the Model module.The results show that the cable-free antenna mast will undergo vibration form transformation at the wind speed of U=13.5 m/s,and the vibration form will change from the first-order mode to the first-order and second-order mixed mode.The lateral amplitude will be extremely small at this wind speed.The numerical simulation results of downwind resistance of the mast are basically consistent with the empirical formula,and the comparison error does not exceed 8.5%.The alternating oscillation of the main vortex of the wake of the cable-free antenna mast is the main reason for its pulsating lateral wind load.