Flow physics and Stokes’ theorem in wind turbine aerodynamics

A viscous lift theorem is derived from a momentum balance and Stokes’ theorem around one section of a wind turbine blade. The theorem is a generalization of the classical Kutta–Zhukovsky lift theorem for the viscous near-field and is validated for 2-D attached and separated flow. The application of the viscous lift theorem within a coupled Navier–Stokes/vortex-panel solver gives insight into the complex 3-D aerodynamics pertinent to wind turbines.