Abstract
Flow visualization tests have been performed to examine the structure of the near-wall flow over a low-aspect ratio straight wing installed at various angles of attack a and chord Reynolds numberRe c=U∞c/ν=1.76×105. The experiments were carried out at two free-stream turbulence levels, ε=0.1% and ε=1%, the latter one having been achieved using a baffling grid. To visualize the flow, termochromic cholesteric liquid crystals and digital processing of video images were used. At the low turbulence level and α=27°, a flow stall on the lee side of the wing was observed, with a pair of largescale vortices rotating in the wing plane. Simultaneously, no vortex structures were observed on the windward wing surface. It was found the flow patterns on either side of the wing significantly changed with increasing free-stream turbulence level. A separation bubble appeared near the leading edge on the lee side of the airfoil at ε=1%, and large-scale stationary longitudinal vortices originated over the wing windward surface. The number and sizes of the longitudinal structures were found to be dependent on the angle of attack.
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Galina Michailovna Zharkova: She graduated from Moskow Power Institute (Russia) and received her Ph.D. degree in Institute of Theoretical and Applied Mechanics (ITAM), Novosibirsk and Doctor of Sci. degree in 1988. She is professor and Head of the Laboratory at the ITAM. Her research interest is related to liquid crystal composites (investigation, development and application in Fluid Mechanics as nondestructive tool for flow diagnostics), as well as thermophysics, optical methods of flow diagnostics. She is an author of more than 115 publications.
Boris Yurevich Zanin: He graduated from Department of Airplane Production, Moscow Aviation Institute, faculty of aircraft construction in 1976 (dipl. engineer). Since 1976 he is employed in the Institute of Theoretical and Applied Mechanics (Novosibirsk). He received Ph.D. in 1987 under supervision of Prof. Viktor Kozlov and Doctor of Sci. degree in 1999. As a leading research scientist, he carried out experimental investigations of laminar - turbulent transition on wings at flight and in wind tunnels. At present the topics of his scientific work are experimental study of spatial vortex structures in separated flows and development of new separation control methods.
Valentina Nikolaevna Kovrizhina: She graduated from Moskow Institute of Physics and Technology in 1977. From 1975 to 1980 she worked at Flight Research Institute (Zhukovski, Moskow region). From 1981 to 1992 her activity was related to experimental aerodynamics at Novosibirsk State University. She received her Ph.D degree in Institute of Theoretical and Applied Mechanics (1999), Novosibirsk, under the supervision of Prof. Galina Zharkova. Her research interests are related to development and application in Fluid Mechanics of optical techniques for flow visualization and measurements, liquid crystals and digital image processing. She is an author of 19 publications in this area.
Anton Petrovich Brylyakov: He studied and received B.Sc. degree in Novosibirsk State University in 2001. His research interests are related to application of liquid crystal thermography and digital image processing.
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Zharkova, G.M., Zanin, B.Y., Kovrizhina, V.N. et al. Free stream turbulence effect on the flow structure over the finite span straight wing. J Vis 5, 169–176 (2002). https://doi.org/10.1007/BF03182426
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DOI: https://doi.org/10.1007/BF03182426