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应用粒子图像测速技术分析了平板断面颤振过程中尾部旋涡变化过程,采用相位平均的方法研究模型周期性振动与旋涡规律性演化之间的关系。当风速低于颤振临界风速时模型尾部旋涡尺度较小,结构振动幅度较小,当风速接近颤振临界风速时尾部旋涡经历了能量从小涡向大涡的传递过程后由能量较大的旋涡控制结构振动,结构振幅明显增加,直到模型振动发散。结合计算流体动力学的数值模拟方法获得颤振时刻模型表面的压力场,采用本征正交分解技术分析模型表面压力的模态特征函数,并根据分析结果对模型表面进行合理分区,利用分块分析的思想研究颤振过程中气流能量输入特点。结果表明:在颤振过程中模型表面波动压力的主控成分向迎风端风嘴漂移;主控波动压力的漂移造成模型通过迎风端风嘴从气流中吸收大量的能量,在一个完整振动周期内,气流输入到振动系统的能量不断增加,而造成结构稳定性的丧失。
Particle image velocimetry was used to analyze the change of aft vortex in the process of plate section chatter vibration. The phase averaging method was used to study the relationship between the periodic vibration and the vortex regular evolution. When the wind speed is lower than the critical wind speed of flutter, the tail vortex scale is smaller and the vibration amplitude of the structure is smaller. When the wind speed approaches the critical wind speed of flutter, the tail vortex undergoes energy transfer from small vortex to large vortex, Control structure vibration, the structure amplitude increased significantly, until the model vibration divergence. The pressure field on the model surface was obtained by CFD numerical simulation. The eigen-orthogonal decomposition technique was used to analyze the modal eigenfunctions of the model surface pressure. The surface of the model was reasonably partitioned according to the analysis results. Analysis of the idea of flutter in the process of energy flow characteristics of the input. The results show that the main component of the fluctuating pressure on the surface of the model drifts toward the windward end nozzle during the flutter process. The drift of the master fluctuating pressure causes the model to absorb a large amount of energy from the airflow through the windward end nozzle, and during a complete vibration period , The energy input to the vibrating system by the airflow is constantly increasing, resulting in the loss of structural stability.