Investigating Chaos in Ocean Acoustics.
1997
Yen, Kang K. | Yan, Jianguo
Chaos is a term assigned to a class of motions in deterministic systems whose time history has a sensitive dependence on initial conditions. Such phenomenon has previously been shown to exhibit in ocean acoustics ray tracing, and called ray chaos by the ocean acoustics community. Since 1995, we have made a further investigation on the ray chaos, as a basic research sponsored by the Office of Naval Research (Grant No. N00014-95-10443). The results of this investigation are presented in this report. Two new topics are addressed. The first is the chaos in three-dimensional (3-D) ray tracing. We study the chaos in Heard-to-Ascension (HA) propagation, and California-to-Hawaii (CH) propagation. Chaos appeared in both cases. Loss of predictability occurred in HA case. However, CH problem was predicted with high accuracy even in the presence of chaos. Comparison between the HA and the CH case leads to a hypothesis on overcoming ray chaos. The signature of chaos in the received signals is discussed. The second topic is the chaos in double-channel propagation. We use the 2-D equations and a double-channel model to study the effects of internal waves on chaos. Then we use the 3-D ray equations and measured sound speed data to conduct a further investigation. Numerical results show that chaos in a double-channel is likely to be induced by internal waves. Much larger chaoticity was observed when measured sound speed data were used.
显示更多 [+] 显示较少 [-]