Turbulent boundary layer on an extended axisymmetric body in the case with air blowing and a rough permeable surface
V.I. Kornilov
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
Keywords: axisymmetric body, turbulent boundary layer, distributed blowing, perforated region, friction
Abstract
Results of numerical and experimental investigations of the efficiency of distributed air blowing through a perforated region of the surface of an axisymmetric body of revolution in an essentially incompressible flow with the Reynolds number ReL = 4,24·106 are reported. The blowing factor Cb is varied in the interval 0-0.00885. The Reynolds number Re** based on the momentum thickness δ** ahead of the perforated region is 5600. As the streamwise coordinate х increases, stable reduction of local friction is observed up to the distance of 600 δ** from the blowing region; the maximum value of local friction reaches 56.5% directly in the region of blowing with the maximum intensity. It is found that spontaneous blowing, which occurs due to the natural difference between the barometric and static pressures in the wind tunnel test section, can also ensure reduction of the skin friction coefficient whose value in the above-noted flow region in the main operation regime is 28.5%. Specific features of the flow around the body of revolution in the case of a rough perforated surface is analyzed through numerical simulations, and it is demonstrated that it is necessary and important to take into account this factor accompanying the blowing process.
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