Open AccessA NEW METHOD FOR CALCULATING RADIATION FROM PARAMETRIC LINE ARRAY
Author(s) -
Qian Zhang
Publication year - 1981
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.30.1479
Subject(s) - fresnel integral , parametric statistics , physics , expression (computer science) , line integral , operator (biology) , radiation , range (aeronautics) , function (biology) , optics , point source , point (geometry) , line (geometry) , field (mathematics) , parametric array , fresnel number , near and far field , mathematical analysis , fresnel diffraction , computer science , integral equation , mathematics , geometry , diffraction , materials science , repressor , chemistry , composite material , biology , biochemistry , evolutionary biology , transcription factor , programming language , statistics , pure mathematics , gene , acoustic wave
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.