Riblet-assisted control of transformation of the L-structure into a turbulent spot
V.G. Chernorai 2, Yu.A. Litvinenko1, V.V. Kozlov1, L. Loefdahl2, G.R. Grek1, and H.H. Chun3
1Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
2Chalmer Institute of Technology, Goeteborg, Sweden
3Pussan National University, South Korea
Pages: 539-548
Abstract
Experimental results are presented on transformation of a solitary L-structure into a turbulent spot and control of this process by means of riblets on the wetted surface in the boundary layer on a flat plate. It is shown that riblets exert a stabilizing effect on transformation of the L-structure into a turbulent spot. The L-structure on a smooth surface is shown to stretch in the streamwise direction and transform into a hairpin vortex, which becomes a turbulent spot further downstream. The intensity of the L-structure on riblets first increases and then decays further downstream, reaching less than half its value on a smooth surface. Finally, the L-structure decays on riblets without forming a turbulent spot.
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