Applying dynamic wake models to induced power calculations for an optimum rotor.

摘要

Recent studies have pointed out that conventional lifting rotors in forward flight have efficiencies far lower than the optimum efficiencies predicted by theory. This dissertation explains how a closed-form optimization of induced power with finite-state models is expanded to successfully reproduce the results for the optimization of induced power given by classical theories for axial flow and for a rotor in forward flight. Results for induced power change in forward flight and for different conditions will help the determination of what produces the efficiency in real rotors to be inferior to the predicted values by theoretical calculations.;Mainly three factors contribute to the decreased efficiency for real rotors: a finite number of blades, the effect of lift tilt and the lift distribution. The ultimate goals of the present research effort are to: (1) develop a complete and comprehensive inflow model, and (2) determine which of these contribute to the drastic increase in induced power.