计算线源声参量阵辐射场的新方法

本文提出一种计算惠更斯积分的新方法,并利用它来研究线源声参量阵。首先将点源函数展开为一个算符对平面波函数的运算,经过计算证明,如果将这个算符对参量阵远场解进行运算,得到的结果即为线源参量阵辐射场的解。其次证明,参量阵的夫琅和费远场解及菲涅耳修正解都可由本文导出,并且证明,菲涅耳修正只是对半束宽角以外的场有贡献。本文还计算了截断参量阵的辐射场,结果表明,这种阵的近场指向性随距离的减小而变尖锐。并且可以预料,实际参量阵辐射场的性质取决于下述三个场参量:kRsin²θ,βR和R_{1关键词：}

A NEW METHOD FOR CALCULATING RADIATION FROM PARAMETRIC LINE ARRAY

Atechnique for analytic evaluation of one-dimension Huygens' integral is proposed. The sound fields of the parametric line array can be analysed by it. Firstly, the point-source function is expanded into an operator on a plane wave function. Putting it into above mentioned integral and calculating it, it is shown that if we make an operation of this operator on the far-field solution, a general expression of radiation from parametric line array can be obtained. Secondly, both Fraunhofer's far-field approximation expression and Fresnel's, nearfield approximation expression are derived from it, but the latter approximation make a appreciable contribution on the radiation only outside the range of half-width angle.Furthermore; the radiation of a truncated parametric line array whose length is R₁ is caleucated. We find that the beam pattern of this array becomes more narrow as decreasing the range. And a prediction can be made that the radiation field of a real parametric array will depend on following three parameters: kR sin²θ, βR, R₁. Finally, basing on this theory, it appears to the author that the inconsistencies in ap-pearenee for some published experiments can be consistent with each other.