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The unsteady characteristics of the flow over thick flatback airfoils have been investigated by means of CFD calculations. Sandia airfoils which have 35% maximum thickness with three different trailing edge thicknesses were selected. The calculations provided good results compared with available experimental data with regard to the lift curve and the impact of trailing edge thickness. Unsteady CFD simulations revealed that the Strouhal number is found to be independent of the lift coefficient before stall and increases with the trailing edge. The present work shows the dependency of the Strouhal number and the wake development on the trailing edge thickness. A recommendation of the Strouhal number definition is given for flatback airfoils by considering the trailing edge separation at low angle of attack. The detailed unsteady characteristics of thick flatback airfoils are discussed more in the present paper., Comment: German Wind Energy Conference 12

CFD studies have been performed to demonstrate the effects of rotation on large wind turbine blades. The 10 MW blade of the Advanced Aerodynamic Tools for Large Rotors (AVATAR) project was selected in the present investigation. In order to demonstrate the rotational augmentation, lift coefficients of the blade sections were compared with the two-dimensional simulations at consistent inflow conditions. The increase of the lift coefficient was observed at the inboard section of the blade, showing the effect of rotation. A significant delay of separation point as well as a massive reduction of the wake size occur at the inboard blade section. The results of the present manuscript provide more information of the rotational augmentation occurring in the near hub region of wind turbine blades., Comment: 11 th EAWE PhD Seminar on Wind Energy in Europe