Boundary Layer Longitudinal Localized Structures Control by Means of Spanwisewall Oscillations
During the last couple of years great attention has been paid to streamwise oriented structures (streaky structures — “puff ” — structures, longitudinal localized structures) in laminar-turbulent transition. One of such examples is a boundary layer flow at high free stream turbulence (FST). In this case, free stream disturbances affect the boundary layer and streaky structures appear inside the boundary layer. In the downstream direction their intensity increases and results in boundary layer turbulence . These mechanisms at the control conditions were investigated qualitatively in . Using obtained knowledge a scheme of laminar-turbulent transition at high FST conditions was proposed . According this scheme, thirst stage is longitudinal localized structures (“puff”-structures) area. Second — region of the incipient spot development. Third — stage of development and interaction between the turbulent spot.
Key wordshigh free stream turbulence boundary layer longitudinal structure
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- 1.Alfredsson P.H., Bakchinov A.A., Kozlov V.V., Matsubara M. Laminar-turbulent transition structures at a high level of a free stream turbulence II IUTAM Symp. on Nonlinear Instability and Transition in Three-Dimensional Boundary Layers: Proc. (Ed. P.W. Duck) Manchester, U.K., 1995. - P. 423–436.Google Scholar
- 2.Matsubara M., Kozlov V.V., Alfredsson P.H., Bakchinov A.A. amp Westin K.J.A. On flat plate boundary layer perturbations at high free stream turbulence level // Int. Conf. on the Methods of Aerophysical Research: Proc., Pt. 1. Novosibirsk, 1996. - P. 174–179.Google Scholar
- 3.Kozlov V.V. The role of localized vortex disturbances in the process of transition to turbulence in a boundary layer // Dynamics of localized disturbances in engineering flows: EUROMECH Colloquim 353: Booklet of summaries. Karlsruhe, 1996. - P. 15–16.Google Scholar
- 4.Kwing-So Choi, Jean-Robert De Bisschop and Brian R. Clayton. Turbulent boundary-layer control by spanwise-wall oscillation I/ Theoretical and applied mechanics: XIXth INTERNATIONAL Congress, Kyoto, Japan, August 25–31, 1996. -P. 376.Google Scholar
- 7.Bakchinov, A.A., Grek, G.R., Katasonov, M.M. amp Kozlov, V.V., Experimental study of the interaction between streaky structures and high-frequency disturbances // Proceedings of the 3rd Int. Conf. on Experimental Fluid Mechanics, Moscow, Russia, 1997.Google Scholar