最小二乘法在管道声学测量中的应用研究  

Study on the Application of Least Square Method in Acoustical Measurement Through Impedance Tube

作　　者：顾晓军[1] 吴志江[1] 吕世金[1] 

机构地区：[1]中国船舶科学研究中心,江苏无锡214082

出　　处：《船舶力学》2003年第2期95-101,共7页Journal of Ship Mechanics

摘　　要：最小二乘法是传统的最优化设计方法之一。在一维传播的管道声学测量中 ,通过对多点测量数据的处理可定量求出入射声场和反射声场 ,并进一步得到声学材料的声学参数和管道的声阻抗。通过在声学管道内布置多个测点 ,采用最小二乘法就能有效地降低单个测点测量值的偶然误差 ,同时直观地反映出管道内声场的分布情况。但运用最小二乘法重建管内声场时 ,协方差矩阵Q的最小特征值λmin对于矩阵奇异性的影响是十分敏感的。为此 ,文中提出了测点等间隔分布的最佳配置方案 ,并对测点位置的选取提出了建议 ,对于测点固定布置但不等间距的管道测量系统 ,通过微量变化试件表面至第一测点距离的方法 ,可相对加密同一帧驻波范围内测点的分布 ,从而极大地提高系统的测量精度。The least square method is one of classical approaches in optimization design,which is also very useful in acoustical measurement of impedance tube.After managing pressure data of multipoints in the tube,this paper has achieved incident and reflected wave components along the tube,acoustical parameters of test material and the impedance of the tube in quantity.By arranging multiple measurement points along the tube and adopting least square method in data processing,this paper greatly reduces random measurement error with single point and apparently reveals pressure patterns of reconstruction sound field in the tube.When adopting least square method to reconstruct sound field in the tube,the minimum characteristic value is very sensitive to examination of the singular condition of the covariance matrix Q. This paper presents an optimal microphone position of equal-distance arrangement and gives some advices an optimal microphone position of equal-distance arrangement and gives some advices about selecting microphone measurment points.For unequal-distance arrangement of microphone and fixed microphone positions, this paper increases measuring points in a frame standing wave pattern artificially by adjusting the distance from the sample surface to the first microphone slightly,and hence greatly increases the precision of the measurement system.

关 键 词：最小二乘法 管道 声学测量 声场分布 声学材料 测点分布 

分 类 号：U174[交通运输工程] TB52[理学—物理]