【摘 要】
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The time sequence of longitudinal velocity component at different vertical locations in turbulent boundary layer was finely measured in a wind tunnel. The conce
【机 构】
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Department of Mechanics
论文部分内容阅读
The time sequence of longitudinal velocity component at different vertical locations in turbulent boundary layer was finely measured in a wind tunnel. The concept of coarse-grained velocity structure functions, which describes the relative motions of straining and compressing for multi-scale eddy structures in turbulent flows, was put forward based on the theory of locally multi-scale average. Based on the consistency between coarse-grained velocity structure function and Harr wavelet transformation, detecting method was presented,by which the coherent structures and their intermittency was identified by multi-scale flatness factor calculated by locally average structure function. Phase-averaged evolution course for multi-scale coherent eddy structures in wall turbulence were extracted by this conditional sampling to educe scheme. The dynamics course of multi-scale coherent eddy structures and their effects on statistics of turbulent flows were studied.
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