Deep-Ocean Dynamics for Environmental-Acoustics Models.
Abstract
A hydrodynamic model for flows in the deep ocean is developed in order to determine the celocity field and sound-speed distribution for use in acoustic transmission problems. A scaling of the governing equations is constructed that explicity includes sound speed. A subsequent pertubation expansion yields a set of approximate equations for motions nearly in geostrophic and hydrostatic balance, such as large-scale, quasi-steady currents and Rossby waves. The stream function for these flows is shown to satisfy either the quasi-geostrophic potential vorticity equation or a simpler limiting case of this equation. The results of the analysis are used to obtain a significant simplification of the ray equations of geometrical acoustics for moving media. For the particular class of flows considered here, the model equations are applicable if the ocean depth is about 1 km or greater and if the spatial and temporal scales of variation of the motions are of the order of 100 km and 10 days, respectively. A solution for a flow such as the Antilles current is derived. Isospeed curves for this solution are shown in a plane perpendicular to the current, and specific features of the curves are discussed and interpreted.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 15, 1975
- Accession Number
- ADA016830
Entities
People
- J. G. Watson
- M. J. Jacobson
- William L. Siegmann
Organizations
- Rensselaer Polytechnic Institute