New Vortex Dynamics Methods for Rotor Free Wake Analysis

摘要

This report summarizes recent work on rotorcraft aerodynamics involving novelmethods for rotor free wake calculations. A new method called Analytical/Numerical Matching (ANM) was developed. ANM is a hybrid analytical and numerical method that achieves accurate results by combining a low resolution numerical solution with a high resolution analytical solution. Although originally developed for vortex dynamics, ANM has proven to be of a general nature. The application of ANM to the rotor wake problem provides accurate answers with a significant reduction in computation time. The use of ANM introduces the opportunity to develop new solution strategies, including Far-Field Linearization and Periodic Inversion. These methods afford the means to obtain accurate solutions Over the entire flight regime. Work involving applications of ANM has also led to a scheme that represents vortex filament dynamics by a hierarchy of nested problems of varying resolution joined by matching solutions. This approach, called ANM with Pyramiding (ANM/P), has reduced calculation times by more than a factor of twenty in some sample problems. Rotorcraft aerodynamics, Vortex dynamics, Free-wake analysis.