CAJ | 학술논문

通过对空泡水筒中螺旋桨进行空泡噪声测量试验,采集了螺旋桨在空化条件和非空化条件下的噪声信号.借助数字信号处理技术对声信号进行频谱分析,研究空泡噪声特征信号在频域的特征和规律,以便判别或预报这类空泡及其噪声特性.此次试验特别引入加速度计,测量了螺旋桨动力仪引起的机械振动信号,并得出其信号对水听器采集的水声信号影响较大,可采用噪声消除方法降低干扰.试验表明,噪声频率在高频时空化噪声比非空化噪声声功率级增加约20 dB.另外,详细介绍了噪声测量系统和测试方法,同时也采用高速摄像机对螺旋桨空泡进行了观测.
통과대공포수통중라선장진행공포조성측량시험,채집료라선장재공화조건화비공화조건하적조성신호.차조수자신호처리기술대성신호진행빈보분석,연구공포조성특정신호재빈역적특정화규률,이편판별혹예보저류공포급기조성특성.차차시험특별인입가속도계,측량료라선장동력의인기적궤계진동신호,병득출기신호대수은기채집적수성신호영향교대,가채용조성소제방법강저간우.시험표명,조성빈솔재고빈시공화조성비비공화조성성공솔급증가약20 dB.령외,상세개소료조성측량계통화측시방법,동시야채용고속섭상궤대라선장공포진행료관측.
This paper investigates the cavitation and non-cavitation noises produced by propellers based on a water tunnel experiment. The power spectrum of the noise is first analyzed through digital signal pro?cessing technologies,where the frequency features and regular patterns of the cavitation noise signal are obtained for forecasting purposes. Particularly,the accelerometers are employed during the experiment to measure the mechanical vibration signal,which reveals its severe interference on the underwater acoustic signal. Thus,a noise reduction procedure is applied to reduce the external noise. The results show that at high frequencies,the sound power level under the cavitating flow condition is 20 dB higher than that under the non-cavitating flow condition. Aside from these observations,the cavitation behavior of the propeller is examined with the help of high-speed cameras,while the measuring system and methods are also dis?cussed in detail.