Turbulence Management by Groove Roughness
Measurements were made of mean velocity profiles for smooth-wall and d-type groove-rough-wall turbulent boundary layers in zero pressure gradient when perturbed by a spanwise rod attached to the wall. Using Coles law of the wall and law of the wake, the skin friction and wake parameter were evaluated from the velocity measurements. It was deduced from the result of evaluation that equilibrium could exist only for rough-wall boundary layers, in which the effect of perturbation approaches monotonically to a new equilibrium state different from that of the original flow. Suggestions are made on the possibilities of drag reduction by providing the boundary layer with the feature of equilibrium.
KeywordsBoundary Layer Skin Friction Turbulent Boundary Layer Drag Reduction Smooth Wall
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