主动来流闭口箱梁气动力时频相关性

基于主动控制的多风扇和振动格栅装置模拟了14种同步二维湍流场,同步测量了参考点处流场特性及相应断面气动力,从时域和频域2个角度分析了荷载展向相关性与来流特性之间的关系,研究发现,来流相关性与气动力相关性并不相同;气动力相关性之间也互不相同.气动力相关性受来流特性影响显著,在大积分尺度来流下,脉动风及荷载空间相干函数并不满足传统e指数形式.为了考虑来流特性对气动力相干函数的影响,提出了一种相干函数模型,较之传统模型,该模型可以反映来流特性对空间相干函数的影响以及气动力与脉动风相干函数间的差异.

Time frequency Coherences of Aerodynamic Loads on a Streamlined Bridge Girder in an Actively Controlled Wind Tunnel

Altogether 14 different two dimensional flow fields were simulated in an actively controlled wind tunnel by using multiple fans and vibration grids. Flow features and aerodynamic loads were measured simultaneously through the simultaneous acquisition facilities. Relationships between spatial coherences of aerodynamic loads and incident flow features were studied in both time and frequency domains. Spatial coherences of both incident flows and aerodynamic forces varied with each other. Spatial coherences of aerodynamic loads were affected by incident flow features. Shape of spatial coherence versus frequency did not always satisfy the exponential law, especially under large scale oncoming flow conditions. A new imperial model was proposed to reflect the influence of incident flow features on the spatial coherences of aerodynamic loads, and to reflect the differences between spatial coherences of aerodynamic loads and incident flows.