An engineering model for yawed conditions, developed on basis of wind tunnel measurements

In the paper, results are presented from a Dutch research project, carried out by the Netherlands Energy Research Foundation, ECN. The project aimed at the development of an improved engineering model for the prediction of the unbalance in the inflow of a wind turbine rotor at yawed conditions. The yaw model was derived from inflow measurements which are performed in the rotor-plane of a 1.2 m diameter wind turbine, placed in the open jet wind tunnel of the Delft University of Technology, DUT in Holland. The model has been validated with load measurements in yaw which were made on several model wind turbines placed in windtunnels and on a full scale wind turbine. In many validation cases, the new yaw model resulted in a considerable improvement of the prediction of the loads at yawed conditions. The project was funded by the Netherlands Agency for Energy and the Environment, NOVEM