摘要
应用粒子图像测试技术(PIV)测试了闭口单箱颤振过程中尾部风嘴附近的旋涡变化过程,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,模型尾部风嘴附近下侧的旋涡控制结构运动状态,结构振动幅度较小;当风速接近颤振临界风速时,尾部风嘴上侧的旋涡尺度明显增大并达到与下侧旋涡相匹配的程度时,结构振幅明显增加,尾部风嘴处上下侧旋涡的交替作用主导了结构的振动。结合计算流体动力学(CFD)的数值计算方法获得颤振时刻模型表面的压力场。通过对模型表面进行合理分区,并利用分块分析的思想研究了颤振过程中气流能量输入特点。分析结果表明振动中的模型通过迎风端风嘴从气流中吸收了大量的能量。在颤振临界风速下,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,造成单箱的颤振多为结构稳定性的突然性丧失。
The process of vortex varying near rear nozzle during flutter of a box section was tested with PIV technique.The relationship between the periodic oscillation of the model and the vortex evolution law was studied using the phase-average method.It was shown that when the wind speed is smaller than the critical flutter wind speed,the structural motion state is controlled by the vortex near the downside of the rear nozzle,so the viration amplitude of the structure is small;then the wind speed is close to the critical flutter wind speed,the scale of the vortex near the upside of the rear wind nozzle significantly increases and matches to the down-side vortex,the amplitude of the structure also increases;the alternating effect of the vortex near the upside and downside of the rear wind nozzle leads to the vibration of the model.The pressure field of the model surface was obtained with the method of CFD numerical simulation.The reasonable partition of the model surface was also made.The features of energy input during flutter was studied by adopting block analysis.The results showed that the model absorbs a lot of energy with the windward end nozzle from the air,in a complete vibration cycle the energy input into the vibration system increases continuosly and leads to suddenly losing structural stability.
出处
《振动与冲击》
EI
CSCD
北大核心
2012年第12期22-27,共6页
Journal of Vibration and Shock
基金
国家自然科学基金(5102114005)
华北水利水电高层次人才资助项目
关键词
颤振
流场机理
粒子图像测速单箱断面
分块分析
相位平均
flutter
flow mechanism
particle image velocimetry
box section
block analysis
the phase-average
