The present study analyses the successive transition steps in the flow around a high-lift wing configuration, as the Reynolds number increases in the low and moderate range (800-10,000), by the Navier-Stokes approach. A very good comparison with a water-channel experiment is achieved. This flow system is mainly governed by two kinds of organised modes appearing successively as the Reynolds number increases: the von Karman and the shear layer mode. A period-doubling scenario characterises the first 2D stages of the von Karman mode up to Reynolds number 2000, where the shear-layer mode becomes predominant. The successive stages of the 3D transition are also analysed in detail. The history of the three-dimensional modes development from a nominally 2D flow configuration is clearly addressed, as well as the quantification of the spanwise wavelength. In a second step, the effect of wall suction has been studied both in 2D and 3D flows around the NACA0012 airfoil at 20 of incidence and a Reynolds number of 800. This study has the objective to optimise the aerodynamic coefficients and to attenuate the mentioned 3D transition effects in the near wake. The receptivity of the flow to the suction is clearly shown and the suction position on the wall has been optimised according to the improvement of the aerodynamics coefficients (minimum of drag coefficient and increase of lift). In the 3D suction case, the optimum 2D suction position is used. Three spanwise suction ways are employed taking into account the spanwise natural wavelength. The secondary instability is removed in the near wake region and a good effect on the aerodynamic coefficients is achieved
Transition to turbulence and control in the incompressible flow around a NACA0012 wing
Umschlag zur Turbulenz und Steuerung in der inkompressiblen Umströmung eines NACA0012-Flügelprofils
2005
10 Seiten, 5 Bilder, 1 Tabelle, 21 Quellen
Aufsatz (Konferenz)
Englisch
Influence of Turbulence Intensity on Flow Field Around NACA0012 Wing at Reynolds Number of 20,000
Springer Verlag | 2022
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