REDUCTION OF BVI NOISE ON GROUND -IN-FLIGHT EVALUATION OF CLOSED-LOOP CONTROLLER

摘要

The individual blade root control (IBC) system installed on a BO 105 helicopter has been successfully tested in the open loop configuration. The flight tests have clearly demonstrated the noise and vibration reduction potential of this technology. The further activities were therefore concentrated on the realisation of a closed loop noise and vibration control system. This paper presents the development and the testing of a BVI (Blade Vortex Interaction) noise control concept. The newly developed control strategy is based on the minimisation of an appropriate BVI index by applying a 2/rev IBC feedback. The in-flight testing of the controller using onboard microphones for BVI noise detection was performed on the BO 105 test helicopter. The reduction of the noise emission measured on ground is documented for several flight conditions.