Free-Wake Analysis of Tandem, Tilt-Rotor and Coaxial Rotor Configurations

A pseudo-implicit, predictor-corrector based free-wake analysis is applied to investigate the tip vortex geometries of tandem, tilt-rotor and coaxial twin rotor systems. Predicted wake geometry results are discussed for the three rotor configurations for several advance ratios ranging from relatively low speed to moderately high speed forward flight conditions. Comparisons are made between computed and measured wake boundaries in the longitudinal center line for the coaxial configuration.