Vortex methods for the computational analysis of rotor/body interaction

This paper describes the development and implementation of a unified model of rotorcraft interactional aerodynamics using advanced methods in vortex dynamics. The model incorporates several recently-developed tools for the analysis of vortex wake dynamics and vortex/surface interaction including: a Constant Vorticity Contour (CVC) full-span free wake model; a method for the prediction of surface pressures caused by close vortex interactions based on Analytical Numerical Matching (ANM); and a new analytical asymptotic analysis of curved vortex interaction with curved surfaces. The development of each of these features of the model is described as is their coupling with a panel method analysis of the fuselage. Model problems are solved to demonstrate the ability of the ANM model to predict inviscid vortex/surface interactions accurately and with greater efficiency and consistency than traditional methods. In addition, fundamental studies of curved filament dynamics near curved surfaces are described, along with correlations of measured and predicted surface pressures. Though the present analysis is limited to inviscid interactions, it nonetheless provides a useful predictive capability for certain classes of realistic wake/airframe interactions.