Estimation of roughness effects on wind turbine blades with vortex generators

Surface degradation of the wind turbine blades lead to a reduction while on the other hand blade add-ons like, vortex generators, lead to an increase in the aerodynamic performance. Within this study, both the reduction due to leading edge roughness and the increase due to vortex generators in the aerodynamic performance are quantified individually first, and then it is investigated if the vortex generators would compensate for the losses due to roughness. Roughness models for the Spalart-Allamaras (SA) and k-ω SST turbulence models are implemented in the open source CFD suite SU2 and validated against theoretical predictions and experimental data. The roughness model is then applied to a commonly used airfoil section, DU97-W-300 and steady RANS simulations are carried out with SU2. Four different conditions are considered-no erosion (clean), eroded (rough), clean blade section with VGs and rough blade section with VGs. Numerical simulations are validated with experimental data for the clean airfoil section and airfoil section equipped with vortex generators. Finally, a preliminary analysis is presented for each of the cases considered on the effect of power production.