Validation of an Actuator Line Method for Tidal Turbine Rotors

摘要

Computations of the blade loading and the local flow field around theModel Rotor Experiments In Controlled Conditions (MEXICO) rotor arepresented using an actuator line method, implemented within the opensource code OpenFOAM. The nacelle and near wake mesh refinementare shown to have little influence on the computed blade loads but asignificant impact on the near wake flow field. In addition, the bladeloads and near wake flow field calculated with 3 different distributionsof the Gaussian smearing parameter ε are compared with experimentalmeasurements. Local chord and lift coefficient scaled smearing distributionsare shown to yield a significant improvement in the representationof the computed tip vortices and also a small improvement in the bladeloading prediction, when compared with a spanwise constant smearingdistribution. Despite these improvements in performance prediction, theperformance of the rotor is shown to be more strongly influenced by thetip correction factor, where considerable improvement is still requiredbefore actuator line methods can represent real rotors with sufficient accuracy.