Effect of the Slot Orientation Angle on Stabilization of a Supersonic Boundary Layer
V. I. Lysenko, V. V. Smorodsky, A. D. Kosinov, A. A. Yatskikh
Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: compressible boundary layer, hydrodynamic stability, slots
Abstract
An experimental study is performed on the influence of surface slots (grooves) with a depth of 0.18 mm (the depth-based Reynolds number is Reh = 1000) with orientation angles φ = 0, 30, 45, and 90° on the stability of a supersonic boundary layer on a flat plate. Experiments with natural disturbances at the free-stream Mach number M = 2 are performed. It is found that the maximum rates of the spatial growth of disturbances decrease as the slot orientation angle decreases from φ = 90° to zero. At φ = 0 and 30°, they become smaller than the corresponding values for a smooth plate. The results obtained show that the instability of the first mode of the supersonic boundary layer, which determines the laminar-turbulent transition at M = 2, can be stabilized by small-depth slots with moderate angles of their orientation (0° ≤ φ < 40°).
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