IBC Effects on BVI Noise and Vibrations - A Combined Numerical and Experimental Investigation

Abstract

In order to explore the potential of Individual Blade Root Control (IBC) for vibration and Blade-Vortex Interaction (BVI) noise reduction, a flight test program was jointly performed by Eurocopter Deutschland (ECD), ZF Luftfahrttechnik (ZFL), Daimler-Benz (DB) and Deutsches Zentrum für Luft- und Raumfahrt (DLR). The tests were conducted with a BO105 helicopter featuring a powerful blade root actuation system and a comprehensive sensor instrumentation. The test matrix covered a wide range of BVI flight conditions with a systematic variation of IBC settings for numerous advance ratios and descent angles. The resulting data demonstrated the strong IBC potential for a reduction of the rotor induced vibrations and BVI noise emissions. Within a combined numerical and experimental investigation the mechanism leading to this vibration and BVI noise reduction was identified and a physical explanation was given.