| With the increasing of the span and flexibility, modern bridges have weaker stiffness and lower damping, thus, they are prone to be damaged under the action of wind. So, it is valuable and important to study wind-resistant stability for bridge. Computational Fluid Dynamics, which is fast maturing in the resent years, can replace wind tunnel test in a certain extent as a useful method to investigate various wind effects on long-span bridges.Based on Fluent which is the CED generic software, the present study about the wind-effects on bridge can be summarized as follows:1. According to the least square method for recognizing the flutter derivatives and the semi-inverse method for determining flutter critical wind speed in detached-forced vibration state, corresponding programs are written based on Matlab platform. The program is validated preliminarily through the classic example of ideal flat plate.2. The flow field numerical model of the streamlined box girder is established according to method of dynamic meshing in this thesis. The flutter derivative and flutter critical wind speed are identified, and Numerical value is closely approximate to the wind tunnel test value.3. The effects of the height of central stabilizers on the aerodynamic stability of streamlined box girder are also studied. The flow field characteristics, flutter derivatives and flutter critical wind speed are analyzed correspondingly. The results indicate that, if the height of central stability board is in the range of0.4time beam height, the settings of central stability board can improve the aerodynamic stability of the streamline box girder.4. The aerodynamic stability of streamlined box girder with different widths of central slotting is investigated via analyze the change of flow field characteristics, flutter derivatives and flutter critical wind speed. The results show that the central slotting can improve the flutter critical wind speed and there is optimal slot width. |
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