旋转运动声源的频率波动修正波束形成方法  

A frequency fluctuation correction beamforming method of rotary motion sound source

作　　者：高建正 陈正武[2] 莫品西 蒋伟康[1] GAO Jianzheng;CHEN Zhengwu;MO Pinxi;JIANG Weikang(State Key Laboratory of Mechanical System and Vibration,Shanghai JiaoTong University,Shanghai,200240;China Aerodynamics Research and Development Center,Mianyang,621000)

机构地区：[1]上海交通大学机械系统与振动国家重点实验室,上海200240 [2]中国空气动力研究与发展中心,绵阳621000

出　　处：《声学学报》2021年第4期576-583,共8页Acta Acustica

基　　金：国家自然科学基金项目(51835008,11874262)资助。

摘　　要：针对前飞状态的旋翼气动噪声信号频率存在周期性波动,且频域波束形成方法只能应用于稳态声源的问题,提出一种频率波动声源的波束形成方法。该方法利用已知的声源频率变化规律进行频率修正,在时域将频率波动信号等效为单频信号,基于该单频信号进行波束形成声源定位,实现了旋转运动的频率波动声源准确定位。数值仿真结果表明,提出的方法能够在频率波动幅值为127 Hz的情况下准确呈现出声源分布情况.在旋翼模型的风洞试验中,利用提出的频域波束形成方法其声成像结果中声源最大能董位置均在旋转轨迹上,而未进行频率修正的波束形成方法结果无法准确呈现出声源的位置.该方法扩展了频域波束形成方法中的单频声源假设,实现了旋转运动声源在频率波动状态下的波束形成,适用于前飞状态下旋翼气动噪声源的声源定位。A frequency compensation beamforming method is proposed which aims to locate aeroacoustic sources of helicopter rotor in forward flight.The sources with frequency fluctuation cannot be located by state-of-art frequency domain beamforming methods,which leads to incorrect source mapping results.The frequency fluctuation of source signal is compensated in the time domain according to the non-constant relative speed between the solid surface of rotating blades and the flow,and an equivalent signal frequency is used in the accurate location locating of the rotary motion sources.The simulation results indicate that sources with frequency fluctuation amplitude of 127 Hz could be located by the proposed method.In the wind tunnel test of the rotor model,the maximum energy position of the sound source in the acoustic imaging results using the proposed frequency-domain beamforming method is near the rotating track,while the results using the beamforming method without frequency correction cannot accurately show the position of the sound source.This method extends the assumption of single frequency sound source in the frequency domain beamforming method,and realizes the beamforming of rotary motion sound source in the state of frequency fluctuation,which is suitable for the localization of rotor aerodynamic noise source in the state of forward flight.

关 键 词：频率波动 声源定位 波束形成 单频信号 频率修正 运动声源 噪声信号 风洞试验 

分 类 号：V211.52[航空宇航科学与技术—航空宇航推进理论与工程]