In the analysis of the aerodynamic performance of wind turbines, the need to account for the effects of rotation is important as engineering models often failed to predict these phenomena. Investigations are carried out by employing an unsteady computational fluid dynamics (CFD) approach on a generic 10 MW AVATAR (Advanced Aerodynamic Tools for Large Rotors) blade. The focus of the studies is the evaluation of the 3D effect characteristics on thick airfoils in the root area. For preliminary studies, 2D simulations of the airfoils constructing the blade and 3D simulations of the turbine near the rated conditions are carried out. The 2D simulations are in good agreement with available measurements within the linear lift region, but the accuracy deteriorates in the post stall region. For the 3D wind turbine rotor results, the prediction is consistent with other CFD computations obtained from the literature. Further calculations of the rotor are conducted at 5 different wind speeds ranging from below to above the rated conditions, which correspond to 5 different angles of attack. The CFD simulations demonstrate that the lift coefficient increases in the blade root region compared to the 2D conditions caused by the centrifugal pumping and Coriolis force via the reduction of the boundary layer thickness and separation delay. The Coriolis force effect decreases with the increasing wind speed and radial position. In addition, the aerodynamic behaviour of the blade inboard region is influenced by the shedding direction of the trailing vortices. The occurrence of downwash is observed causing a local increase in the drag coefficient.

No abstract

No abstract

No abstract

No abstract

No abstract

No abstract

The present studies deliver the computational investigations of a 10 MW turbine with a diameter of 205.8 m developed within the framework of the AVATAR (Advanced Aerodynamic Tools for Large Rotors) project. The simulations were carried out using two methods with different fidelity levels, namely the computational fluid dynamics (CFD) and blade element and momentum (BEM) approaches. For this purpose, a new BEM code namely B-GO was developed employing several correction terms and three different polar and spatial interpolation options. Several flow conditions were considered in the simulations, ranging from the design condition to the off-design condition where massive flow separation takes place, challenging the validity of the BEM approach. An excellent agreement is obtained between the BEM computations and the 3D CFD results for all blade regions, even when massive flow separation occurs on the blade inboard area. The results demonstrate that the selection of the polar data can influence the accuracy of the BEM results significantly, where the 3D polar datasets extracted from the CFD simulations are considered the best. The BEM prediction depends on the interpolation order and the blade segment discretization.