中文摘要：

为研究平板气动力系统的非线性特征,基于非定常雷诺时均Navier-Stokes（RANS）方程和SSTk-ω湍流模型,数值模拟了在单位位移激励下平板非定常运动的绕流场,获得了作用在平板上的气动力时程,并基于Volterra理论开展了平板非线性气动力系统识别.研究表明,本文建立的平板非线性气动力模型能对一定频率带宽和一定幅值范围的激励产生合理的响应;在本文研究的强迫运动位移幅值和频率范围内,平板非线性气动力模型响应没有表现出对振动幅值和频率的明显相关性,且其气动力的非线性效应并不明显,因而可以认为小攻角下的平板绕流属于气动力弱非线性系统.本文研究证明了CFD模拟在桥梁主梁气动力系统识别上的明显优势.

英文摘要：

In order to investigate the characteristics of nonlinear aerodynamic system of a thin plate, flow field around the thin plate under forced unit impulse excitation was simulated by the unsteady Reynolds-averaged Navier-Stokes （RANS） equations and SST k-ω turbulent model, and time histories of aerodynamic force were obtained. The nonlinear aerodynamic system of the thin plate was then identified based on the Volterra theory. The investigation indicates that the present aerodynamic model can provide reasonable output under the excitation within the defined ranges of frequency band and amplitude. Moreover, under the present range of forced frequency and amplitude, no clear dependence of model response on the frequency and amplitude is observed. It is also found that the aerodynamic nonlinearity of the thin plate is not significant, and the flow around the thin plate can be considered as an aerodynamic system with weak nonlinearity. This study confirms that the CFD method is of remarkable advantage for the identification of aerodynamic system of bridge girders.