Experimental Investigations on Tip Vortex Trajectory and Core for Helicopter Rotors

摘要

By the PIV technique, experimental investigations on the rotor blade tip vortices, vortex core dissipationrnand wake boundary for a rotor model using a new facility method are studied in hover and transition state.rnThe variations of tip vortices and vortex core radius with wake age at different blade collective-pitch anglesrnhave get. It gives a base for theory model. As a result, the contracts of rotor blade tip vortices in radial arernmore strength and displacements in axial are bigger with pitch angles in hove. But the contracts in radialrnare almost sameness in transition state. And Vortex core radius is bigger with wake age or pitch angles inrnhover.