Coarse, fast, and still accurate? Comparing corrections for the actuator line model

Abstract The actuator line method for modeling wind turbine blades in wind farm flow simulations often offers a good compromise between accuracy and computational cost. A variety of methods have been proposed to correct the force prediction by the actuator line near the tip and root due to smearing the force in the flow domain. This article compares the two most commonly used methods (the filtered lifting line and the vortex-based smearing correction) in terms of accuracy, applicability and computational performance. Both corrections perform well for a single turbine, significantly reducing the force and power overprediction. The effect on power is larger than on thrust. Applying the corrections leads to more accurate results even at lower resolutions. The application of the corrections in an ALM simulation of a wind farm with 30 turbines reduces power by up to 10% compared to a case without correction. Different turbines in the farm are affected differently. The improvements in accuracy due to the corrections far outweigh the additional computational cost.