有限长管道端部活塞声源辐射特性研究

Research on radiation characteristics from piston sound source at the end of finite pipe

为研究有限长管道端部活塞声源的辐射阻抗和辐射特性,首先在理论上定性分析了该问题与半无限长开口圆管终端辐射问题的区别和可以近似的条件;然后采用结构有限元耦合流体有限元耦合流体边界元(FE-FE-BE)法,定量研究了两个问题中辐射阻抗的异同;最后通过仿真算法研究了管道长径比、矩形活塞宽长比等因素对管端活塞声源辐射特性的影响.结果表明:当ka<0.5时,圆管端活塞声源辐射阻抗与半无限长开口圆管终端辐射阻抗几乎完全相同,当ka>1时,二者存在一定差别;管道长径比对管端活塞声源的辐射特性影响有限,而矩形活塞宽长比对声源的辐射阻抗和指向性影响显著.

To study the radiation impedance and radiation characteristics of the piston sound source at the end of a finite pipe,the differences between this problem and the radiation at the end of the semi-infinite open circular pipe,and the approximate conditions of the two were qualitatively analyzed in theory.Then,the structural finite element coupled with fluid finite element coupled fluid boundary element(FE-FE-BE)method was used to studied quantitatively the differences of impedance in the two problems.Finally,the effects of pipe length-diameter ratio,rectangular piston width-length ratio on the sound source radiation characteristics of the piston at the pipe end were studied by simulation algorithm.Results show that when ka<0.5,the radiation impedance of piston sound source at the end of circular tube is almost equal to that at the end of semi-infinite open circular tube,and there is a difference when ka>1.The length-radius ratio has limited effects on the radiation characteristics of piston sound source at pipe end,while the width-length ratio of the rectangular piston has a significant effect on the radiation impedance and directivity.