Actuator disk theory and blade element momentum theory for the force-driven turbine

The Actuator Disk Theory and the Blade Element Momentum Theory (BEMT) are widely applied in the field of tidal and wind turbine design. The current BEMT turbine design method is based on the assumption of achieving the Betz limit when the axial induction factor (a) reaches 13. But this only applies to turbines driving by a constant velocity, i.e. the velocity-driven turbine. This paper introduces a new type of turbine, namely the force-driven turbine which by its name is driven by a constant force.