Open AccessON APPLICATIONS OF PARAMETRIC ACOUSTIC SOURCES TO SHALLOW WATER
Author(s) -
Qian Zhang,
Shao Dao-yuan
Publication year - 1986
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.35.1374
Subject(s) - parametric array , parametric statistics , acoustics , physics , rayleigh scattering , sound pressure , point (geometry) , power (physics) , sound power , mathematics , optics , sound (geography) , statistics , geometry , thermodynamics
As is shown by westervelt, the difference-frequency sound pressure of the parametric array in the far field is proportional to the second power of f/f0, the downshift ratio of the frequency. However, a different result may occure in the near field, especially, when the distence to the field point is much less than the length of the parametric array, but larger than R0, the Rayleigh length of the transducer. In this paper, our previous theory is applied to the case of shallow water and an expression for the parametric array design has been given. It is shown that the parametric pressure is proportional to Ro, instead of proportional to the length of the parametric array or to the second power of f/f0. Futhermore, an analysis for Moffett and Mellen's theory is also made in this paper and on identical expression has been obtained. Finally, an experiment is carried out in a pool and the results obtained support the theory.