Affiliation of Author(s):航空学院
Journal:Hangkong Xuebao
Abstract:Harsh blade-vortex interaction (BVI) noise will be generated when a helicopter is flying at a moderate speed level flight or descending. Based on the modified Beddoes wake/blade structural dynamics coupling model and Farassat 1A formula, a rotor BVI airload and acoustics prediction method is proposed, in which the influence of higher harmonic control (HHC) can be included. The additional tip vortex vertical displacement caused by HHC is derived from time integration of higher harmonic inflow, and a transfer function that relates single HHC input to resulting response at the same and neighboring frequencies is identified by blade dynamic characteristics. The rotor airload of the baseline case in higher harmonic control aeroacoustics rotor Test II (HART II) is investigated and compared with experimental data firstly. The influencing mechanism and varying pattern of the rotor acoustic property at different 3/Rev control phases is then assessed. The results show that blade dynamic characteristics, especially torsional behaviors, are important for effectiveness of higher harmonic control. Selection of HHC phase input is significant to BVI noise control, and irrational HHC phase input will worsen noise radiation. © 2017, Press of Chinese Journal of Aeronautics. All right reserved.
ISSN No.:1000-6893
Translation or Not:no
Date of Publication:2017-07-25
Co-author:Wang, Liangquan,syj,Xia, Runze
Correspondence Author:xgh
Date of Publication:2017-07-25