A Study on Aerodynamic and Acoustic Characteristics of Advanced Tip‐Shape Rotors

A hybrid method, based on a Navier‐Stokes/full potential/free‐wake solver, is used to simulate the three‐dimensional viscous flow over a rotor with advanced tip shapes in both hover and forward flight conditions. The hybrid solver, combined with the Kirchhoff method, is also used to predict the rotor noise. The transonic flow characteristics of the rotor with rectangular, swept, tapered and anhedral tips are simulated and investigated. Based upon the numerical analysis results, a new and unconventional tip is proposed. The simulation results for the unconventional rotor tip are compared with several other conventional tips. It is clearly shown that the unconventional tip has significant advantages over the other tips considered in this study in suppressing the supersonic flow and improving the aerodynamic performance and acoustic characteristics. Experimental investigations for the unconventional rotor tip and other conventional tips in hover condition are also carried out and the experimental results of the unconventional rotor tip are compared with those of the rectangular and constant‐swept tips. The experimental results demonstrated the benefit of the unconventional rotor in increasing hover performance and reducing noise level when compared to two other rotors.