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Vortex Structures in Turbulent Boundary Layers

The structure of turbulent boundary layers has recently been studied in detail. Using the hydrogen, bubble technique, Kline et al have detected intermittent formation of low-speed streaks very close to the surface, which lift away, thereby forming local inflexions in the velocity profile. These amplify disturbances, producing eddies which are ejected into the outer part of the layer. Black has proposed a turbulence model consisting of periodic horseshoe vortices within the layer, in which the longitudinal legs are stretched as they move through the comparatively quiescent layer.