22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-3.1.2

FLOW VELOCITY INVESTIGATION BY EMBEDDED LASER DOPPLER VELOCIMETRY ON 3D OSCILLATING WINGS

E. Berton, C. Allain, D. Favier, C. Maresca
University of Méditerranée, France

Keywords: aerodynamics, boundary-layers, laser velocimetry, oscillating wings

The present paper concerns an experimental investigation of the unsteady boundary-layer on a flat plate model oscillating in a 3D flow configuration. The study emphasizes on the characterization of the tangential and normal velocity field (U,V) in the immediate vicinity of the moving surface. In the present study, a new Embedded Laser Doppler Velocimetry (ELDV) measurement method, suited for unsteady boundary-layer investigation has been developed. Using this ELDV method, unsteady flow features on transition and separation/reattachment of the boundary-layer are investigated in both steady and unsteady flow configurations. The flow unsteadiness is generated by oscillating the model either in pitch or in translation, and also in a combined translation/pitch motion, at a fixed upstream Reynolds number Re=105 and for various conditions of mean incidence of the airfoil (a0), reduced frequency and reduced amplitude of oscillations (k, ?). Steady and unsteady measurements of the (U,V) components have been performed along the upper-side of the flat plate model and at different spanwise locations. Especially the results obtained on the (U,V) velocity profiles clearly exhibit the influence of the finite span of the model, on the transition, separation and reattachment phenomena of the boundary-layer.

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