Separate Determination of Coexisting Components of Aerodynamic Drag on Rotors

Three approaches -- a wake-integral procedure, a viscous theory of aerodynamics and an integro-differential method for Navier-Stokes flows -- will be fully developed and consolidated to create a new technology for studies of aerodynamic drag associated with unsteady flows. These new approaches deal with theoretical, experimental and computational aspects of the aerodynamic drag problem. They utilize integral expressions derived from vorticity formulations of the Navier-Stokes equations. With these integral expressions, aerodynamic drag on a solid object can be determined using only a limited amount of information about the trailing vortical wakes flow. Coexisting drag components on the solid object can be individually determined. In the Phase I work, an investigation of the hovering rotor problem will be performed. Wake integrals will be derived and computer codes will be prepared for separately evaluating drag components on hovering rotors using available wake data. The viscous theory of aerodynamics and the integro-differential Navier-Stokes solver will be extended to the hovering rotor application. The feasibility and the practicality of the new technology as applied to the problem of the rotor in forward flight and to other unsteady flow problems will be demonstrated.