A Novel Wind Turbine Wake Steering Model Employing the Ainslie Velocity Deficit

Wind turbine wakes are an important source of production losses in wind parks, and strategies to mitigate these effects are being explored. One such strategy is yaw steering, where a wind turbine is purposefully misaligned with the wind to deflect its wake away from a downstream turbine, increasing overall farm power production. In order to optimize yaw steering control, fast and accurate models for wake deflection are necessary. Several models have been proposed in literature, often based on approximations of the wake shape. In the present work, a new model is proposed that computes wake deflection based on the result of the Ainslie wake deficit model used in the Dynamic Wake Meandering (DWM) approach that has recently entered the IEC61400 standard for wind turbines. The proposed formulation makes few additional assumptions and introduces no additional fitting parameters beyond those of the DWM wake deficit model. Results obtained using the new methodology are compared to two models from literature and to LES-ALM simulations in a limited number of cases, showing satisfactory results. More extensive comparisons in a variety of cases should be performed in order to better evaluate the proposed methodology. Possible future improvements to the presented formulation are put forward.