Deepocean dynamics for environmentalacoustics models
Abstract
A hydrodynamic model for flows in the deep ocean is developed in order to determine the velocity field and soundspeed 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 largescale, quasisteady currents and Rossby waves. The stream function for these flows is shown to satisfy either the quasigeostrophic 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.
 Publication:

Unknown
 Pub Date:
 November 1975
 Bibcode:
 1975dode.rept.....W
 Keywords:

 Acoustic Properties;
 Deep Water;
 Fluid Dynamics;
 Mathematical Models;
 Noise Pollution;
 Ocean Models;
 Lesser Antilles;
 Ocean Currents;
 Rossby Regimes;
 Sound Transmission;
 Acoustics