For optimal structural design of wind turbine blades, aerodynamic loads need to be estimated at all wind and operating conditions. Under parked conditions or during an emergency stop or in the event of a sudden gust, the blades can experience very high angles of attack (AOA). Generally, loads at these high AOA are design driving and hence an accurate estimation of force coefficients at these conditions are critical for efficient design. Experimental investigation of airfoils at high AOA in a wind tunnel is always a challenge due to blockage effects, Reynolds number limitation and large unsteady wake motion. Numerical simulations have their own deficiencies mainly associated with the limitations of turbulence models. Empirical formulas which are derived from experimental data for a variety of airfoils have been used with some degree of success. One such empirical formula proposed by C. Lindenburg is based on a limited set of airfoil geometry parameters like leading edge radius and wedge angles. In this study a CFD based numerical investigation is carried out on simplified airfoil geometries to validate the assumptions made in Linderburg’s formula.

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