Appraisal and calibration of an aerodynamic moment correction in the actuator line model

The Actuator Line Model (ALM) is commonly used for moving airfoil simulations since it allows for load predictions with reduced computational cost compared to simulations that resolve the airfoil geometry. We implement an aerodynamic moment correction in the ALM simulations, which involves introducing two additional opposite body forces of equal magnitude, applied at a distance such that they generate the corresponding pitching moment. The uncertain parameters are the moment regularization kernels for these forces, i.e., their Gaussian spreading and the distance between these forces and the aerodynamic center. In addition to these two parameters, the lift and drag regularization kernels, which were already present in the original version of the ALM, had to be adapted for the new force configuration. We performed a stochastic sensitivity analysis to assess the effect of the three uncertain parameters on the wake flow features for a simulation of the NACA0012 airfoil and benchmark them against a resolved simulation. Through a comparison with the latter, we also calibrate the ALM parameters. The calibrated moment correction improves the ALM wake predictions, particularly in the far wake region. The most relevant parameters are the two force spreading kernels. In contrast, the distance between the application points of the forces is mainly used for fine-tuning.