Numerical Analysis Of Galloping Response Of Rectangular Cross-Section Twin Towers

The large amplitude and low frequency vibration of blunt structure--galloping was easy to occur at a certain wind speed when wind cross section. Under the action of wind loading, the aerodynamic parameters and the change rate of the attack angle of the building are the key factor of the galloping. In the study of galloping, the key is aerodynamic parameters of building section. The aerodynamic parameters of Double-tower building are very different from that of single tower, because the flow is interfered by the two towers. The aerodynamic characteristics and galloping of double-tower at Shapingba railway station at many kinds of section and spacing of them were researched by numerical simulation, and the critical wind speed of galloping under different conditions is analyzed in this paper. The main work of this paper is as follows:① A comparative study of turbulence model. The aerodynamic characteristics of different turbulence models in double-tower are analyzed by numerical simulation. The mean aerodynamic force coefficient of Standard k-ε, RNG k-ε, Realizable k-ε, Standardk-ω and SST k-ω models is calculated at 0°, 15°, 30°, 45°, 60°, 75° and 90°angle of direction by FLUENT. By comparison with existing literatures, Standard ke was considered the best turbulence model of this engineering project.② Parametric design of section and spacing of double-tower building. A numerical analysis of the influence of the aerodynamic characteristics of the double-tower is studied by change the tangent shape and the spacing. The mean aerodynamic force coefficient of Standard k-ε model is calculated at different correction rate(0.05, 0.1, 0.15 and 0.2) and different spacing(0.5D, 1.5D, 2D and 3D, D is the width of a building) by FLUENT.③ Finite element analysis of galloping response of double-tower building. A spatial beam element model is used to study the galloping of the double-tower building under different wind direction. The galloping of double-tower tall building under different tangent shape and spacing are discussed in depth. According to D’alembert’s principle, the dynamic equation of beam element is established. From the mean aerodynamic force coefficient have been calculated, the galloping displacement amplitude of along-wind, across-wind, torsion and the Critical wind speed of each case were received. The analysis shows that the fillet correction can reduce the galloping response of the double-tower building more effectively, and the most unfavorable wind direction angle of this project is located near 10 degree.