Aerodynamic Characteristics Of Inclined Cables By On CFD Method

With the increase of the bridge span, the cable-stayed bridge becomes a main type of the bridges. Due to the reduce of bridge structures stiffness, and the damping and vibration frequency, the bridge will easily resonate under the action of the natural wind. The wind-resisten ability of the cable-stayed bridges almost becomes the key of construction and operating. As one of the main structures member of the cable-stayed bridge, the cable wind-resistent ability of cables is more important. The rain-wind-induced vibration of cables is with large amplitude, and cause some or all cables in some bridgesd, which induces great economic losses. Therefore, the research on aerodynimac characteristic of inclined cables under wind-and-rain is very necessary.The hazard caused by wind-rain induced vibration is reviewed in the beginning of the thesis. Subsequently, some cables are simulated by CFD methods.Firstly, aerodynamic coefficients of cables without rivulet are analyzed by steady and unsteady method. Comparing the aerodynamic coefficients obtained by the two methods, the suitable method is adopted. In the other hand, the aerodynamic coefficients of cables without rivulet are analysed using two-dimensional and three-dimensional model, and then the analysis results of two models are compared.Secondly, aerodynamic characteristic of cables with rivulet is analyzed in 2-D form considering many factors such as the diameter of cable, the wind velocity, the shape of rivulet, the dimension of rivulet, the position of rivulet. And then the effects of the factors on aerodynamic coefficients are discussed. Then the aerodynamic coefficients of the cable with rivulet are compared with those of the cable with-out rivulet. So the influence of these factors mentioned on the rain-induced vibration of inclined cables are explored. Furthermore, aerodynamic coefficients of cables with rivulet are analyzed three-dimensional model.Finally, the cable with water drops is simulated. Aerodynamic coefficients of the cables with drops with single row and multi-row drops are determined by CFD. And the influences of water drops on rain-induced vibadtion is discussed.