The actuator disk is a concept often used in wind turbine aerodynamics, where the action of the turbine on the flow is averaged over time and space. This simplification stills retain sufficient physical information for wind turbine aerodynamic design. Its limitations are essentially related to the impossibility to model the blade shed vorticity. This paper presents a more general approach that uses rotating actuator surfaces carrying velocity and pressure discontinuities which are set from knowledge of the circulation around the model blade sections and using blade element analysis. The mathematics of rotating actuator surfaces, as well as an application to the TUDelft rotor are presented in this paper. The results are encouraging.