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通过风洞试验测试了箱梁的颤振性能,根据流固弱耦合的计算策略并结合动网格技术模拟了箱梁的颤振过程。针对固体模型在流场中的运动受网格尺寸限制且易造成网格变形过大导致计算失败的问题提出了动网格弹簧系数分层设置的解决办法。给出了气流输入到振动模型的气动能量计算公式和模型表面区域气动能量比的定义,并从能量平衡的观点给出了颤振稳定判据。通过对振动模型气动能量特性的研究发现箱梁迎风侧风嘴是气动能量的主要输入部位,并且在一个完整的振动周期内气流输入到振动系统的能量不断增加,从而造成箱梁振动稳定性的丧失。将数值模拟获得的振动断面周围的流场采用了相位平均的方法进行了处理,分析了箱梁颤振状态下尾部旋涡的演化规律。应用本征正交分解技术(POD)分析了箱梁表面压力的空间分布特征。研究结果表明箱梁颤振过程中表面压力的主要组成部分向模型迎风侧的风嘴漂移。
The flutter performance of the box girder was tested by wind tunnel test. The flutter process of the box girder was modeled according to the computational strategy of fluid-solid coupling combined with the moving grid technique. Aiming at the problem that the motion of the solid model in the flow field is limited by the mesh size and the deformation of the mesh is too large, which leads to the calculation failure, a solution to the hierarchical setting of the dynamic mesh spring coefficient is proposed. The calculation formulas of aerodynamic energy input into the vibration model and the definition of the aerodynamic energy ratio of the model surface area are given, and the criterion of flutter stability is given from the viewpoint of energy balance. Through the study on the aerodynamic characteristics of the vibration model, it is found that the windward side of the box beam is the main input of aerodynamic energy, and the energy input into the vibration system is increased continuously during a complete vibration cycle, resulting in the vibration stability of the box girder Lost. The flow field around the vibrational section obtained by numerical simulation is processed by the phase averaging method, and the evolution law of tail vortex under the flutter of box girder is analyzed. The characteristics of the spatial distribution of box girder surface pressure were analyzed by using the method of intrinsic orthogonal decomposition (POD). The results show that the main component of the surface pressure in the flutter of the box beam drifts toward the tuyere on the windward side of the model.