不同交通流状态下桥梁气动导数的风洞试验研究

Wind Tunnel Experimental Study of Bridge Aerodynamic Derivatives in Different Traffic Flow States

为了考虑实际运营车辆对桥梁气动导数的影响,根据车辆密度模拟了三种交通流状态,基于强迫振动装置,分别对每个交通流和无车状态下的桥梁气动导数进行风洞试验研究,讨论了不同攻角下不同车流的车辆对桥梁气动导数的影响,探究了车辆对气动导数影响的百分比以及气动导数变化量的变化规律。研究结果表明:不同攻角下不同车流的车辆均对直接导数A*2、H*4和交叉导数A*4、H*2影响显著,A*2、A*3变化量随着折减风速有一定的变化规律。虽然不同攻角下不同车流的车辆对气动导数的影响程度及影响规律不同,并且车流的繁忙程度对大多数气动导数的影响规律不明显,但是车辆对桥梁气动导数的影响不容忽略。

In order to take into account the effect of actual operating vehicles on the bridge aerodynamic derivatives,according to vehicle traffic density,three traffic flow states were simulated,wind tunnel experimental study of bridge aerodynamic derivatives was carried out in every traffic flow state and state without vehicle,based on a forced vibration device.The influence of vehicle in different traffic flow states and at different wind attack angles on bridge aerodynamic derivatives was discussed;the influence percentage of vehicles on aerodynamic derivatives and the variation of aerodynamic derivatives with vehicle deceleration were investigated based on experimental results.Results show that all vehicles in different traffic flow states and at different wind attack angles obviously impact the direct aerodynamic derivatives A＊2,A＊4 and cross derivatives H＊2 and H＊4.The variation of A＊2 and A＊3with wind deceleration is obvious and presents certain regular pattern.Though the influence of vehicles in different traffic flow states and at different wind attack angles on aerodynamic derivatives is different,and the influence of traffic flow density on most aerodynamic derivatives is not obvious,the influence of vehicles on bridge aerodynamic derivatives can not be ignored.