THE SPACING OF STREAKS IN UNSTEADY TURBULENT WALL-BOUNDED FLOW
THE SPACING OF STREAKS IN UNSTEADY TURBULENT WALL-BOUNDED FLOW
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DOI：
10.1063/1.868192
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发表时间：
1994-07-01
影响因子：
4.6
通讯作者：
HWANG, JL
中科院分区：
文献类型：
--
作者：
BRERETON, GJ;HWANG, JL
The spacing of streaks of low-speed fluid has been studied experimentally in a wall-bounded turbulent flow in which sinusoidal unsteadiness was superposed on an otherwise steady mainstream over a range of frequencies. The modulation of phase-conditioned streak spacing about its mean value does not follow the steady wall-flow relation of lambda u(tau)/v equal to a constant. Instead, it is quite accurately described by a local length scale that models the momentary value of the total shear distortion of large eddies of the flow. This single shear-distortion length scale also correlates well with the streak spacing measured in steady wall-bounded flows and in unbounded homogeneous turbulent flow at high shear rates. The apparent generality of these results implies that the streak-spacing selection mechanism depends strongly on the strain history of large-scale coherent motions and so should be investigated in the context of the coupled straining processes of turbulence production.
