A Numerical and Experimental Investigation of a Gurney Flap on a Newman Airfoil

Timothy Michael Laughlan

Abstract


A Gurney flap is a form of high-lift device, used to increase the lift-to-drag (L/D) ratio of a wing. The interesting thing about the Newman airfoil shape is that it encounters a continuous adverse pressure gradient aft of the maximum thickness-to-chord (t/c) position. This causes the airfoil to be prone to separation near the trailing edge. The provision of a Gurney flap alleviates this, since it gives the airfoil an effective camber. The aim of this research was to examine the effect of the height of a Gurney flap in alleviating this separation and thus to improve the L/D ratio. This was achieved through wind tunnel experiments, including surface-oil-flow-visualisation to see where the flow separates on the airfoil. Computational Fluid Dynamics (CFD) simulations were also conducted to compare the experimental data thus validating the CFD and also validating previous research including the hypothesised trailing edge flow structure around a Gurney flap.

Keywords


Fluid mechanics; aerodynamics

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