The transient wave fields in the vicinity of the elliptic, hyperbolic, and parabolic umbilic caustics
作者:
Michael G. Brown,
期刊:
The Journal of the Acoustical Society of America
(AIP Available online 1986)
卷期:
Volume 79,
issue 5
页码: 1385-1401
ISSN:0001-4966
年代: 1986
DOI:10.1121/1.393666
出版商: Acoustical Society of America
关键词: WAVE PROPAGATION;CATASTROPHE THEORY;GEOMETRICAL ACOUSTICS;PHASE SHIFT;TIME DEPENDENCE
数据来源: AIP
摘要:
The caustics of high‐frequency wave propagation may be classified using catastrophe theory. In this paper, we examine the transient wave fields in the vicinity of the elliptic, hyperbolic, and parabolic umbilic catastrophes. Analytical results are presented which describe the time‐dependent wave field due to an impulsive source on and at large distances in each control direction away from the most singular point of each of these three catastrophes. Numerical results are presented which show the smooth variation of these transient wave fields as each control parameter is independently varied. These results are compared to previously derived results on the transient wave fields in the vicinity of the cuspoid catastrophes (the cuspoid and umbilic catastrophes have coranks 1 and 2, respectively). It is found that the transient wave fields in the vicinity of the cuspoid and umbilic catastrophes differ with regard to the temporal structure of the wave field on the most singular point of each catastrophe, the manner in which these temporal structures unfold, and the phase shifts which individual rays undergo as a result of touching one of the catastrophes.
点击下载:
PDF
(1639KB)
返 回