Rotor wake engineering models for aeroelastic applications

Results from the EU AVATAR project have indicated vortex methods generally to be in good agreement with computational fluid dynamics simulations for resolving rotor aerodynamic forces in a variety of operational and inflow conditions. Limitations of the more crude blade element momentum method, most widely used in industry, have been exposed. Although not as expensive as computational fluid dynamics, the application of vortex methods to resolve rotor aerodynamics in wind turbine design and loads calculations is still hindered by its computational burden. An increase in computer power and parallelization has helped over the decades, but an efficiency boost is required to make the last step. The effect of simplifying the far wake description on predicted loads as well as computational effort is investigated for a variety of load cases. Results indicate that dynamic and time averaged loading characteristics are preserved when the mid to far wake grid resolution is reduced. The applied wake reduction is a promising technique leading to desktop design load calculations using vortex wake methods. (paper)