科研之友
微信
新浪微博
Facebook
分享链接
摘要
A suite of computational tools capable of predicting in-plane low-frequency rotorcraft noise and its control using active flaps operating in closed-loop mode is developed. A combined code, consisting of Active VIbration and NOise Reduction (AVINOR), a comprehensive code for active control of vibration and noise, and an acoustic code called HELIcopter NOIse Reduction (HELINOIR), is validated against wind tunnel tests. The in-plane noise reduction obtained with a single 20% chord plain trailing edge flap for a rotor configuration resembling the MBB BO-105 during level flight at a moderate advance ratio is studied. Different configurations of far-field and near-field feedback microphone locations were examined. A near-field microphone located on a hypothetical left boom position was found to be at the best location and produced an in-plane noise reduction of up to 6 dB. However, this noise reduction was accompanied by an out-of-plane noise increase of 18 dB and a 60% increase in the vertical hub shear. These penalties can be partially alleviated by using a dual-plain-flap configuration.
- 出版日期2017-10
