Investigation On The Inflow And Aerodynamic Response Of Rotors In Maneuvering Flight

The inflow and aerodynamic response of the rotor at the maneuvering flight conditions is a challenging topic in the field of rotorcraft aerodynamics. In this paper, the rotor inflow and aerodynamic response during pitching or rolling maneuver flight have been analyzed based upon the dynamic vortex tube model and the augmented Pitt-Peters dynamic inflow model.As the background of work, the current research on the aerodynamic characteristics of the rotor in maneuvering flight is introduced briefly, and it is pointed out that the rotor aerodynamic problem in pitching or rolling maneuver flight due to the aerodynamic change is resulted from rotor angular motions.In Chapter 2, an analytical method for rotor inflow during maneuvering flight is given by combining the curved vortex tube model and the straight vortex tube model. In Chapter 3, as numerical examples, the rotor inflow characteristic and the induced velocity distribution of a model rotor without angular motion are calculated based on the constructed vortex tube model and computational code, and the calculated results are compared with the available experimental data to show the validation of the present method. Then the influences of the pitching and rolling rates on rotor inflow in hover and forward flight are calculated and analyzed respectively.In Chapter 4, the Pitt-Peters inflow model is augmented including the influence of the wake distortion in maneuvering flight. Also, a dynamic wake distortion model based on the previous studies is developed.In Chapter 5, the blade flapping motion equation is derived to construct a model for calculating the flapping response considering the maneuver effects, and also a rotor trimming model is presented.In Chapter 6, by combining the augmented Pitt-Peters inflow model, the dynamic distortion wake model, the blade flapping motion equation and the rotor trimming model. A computational method for the inflow and aerodynamic response during the pitching and rolling maneuvering flight is developed. Using the method, the rotor inflow and dynamic response characteristics for the maneuvering flight conditions is calculated and analyzed, and some new results are obtained.