Application of the ideas and techniques of classical fluid mechanics to some problems in physical oceanography

This review makes a case for describing many of the flows observed in our oceans, simply based on the Euler equation, with (piecewise) constant density and with suitable boundary conditions. The analyses start from the Euler and mass conservation equations, expressed in a rotating, spherical coordin...

Full description

Bibliographic Details
Published in:Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Main Author: Johnson, R. S.
Format: Article in Journal/Newspaper
Language:English
Published: The Royal Society 2017
Subjects:
Online Access:http://dx.doi.org/10.1098/rsta.2017.0092
https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.2017.0092
https://royalsocietypublishing.org/doi/full-xml/10.1098/rsta.2017.0092
Description
Summary:This review makes a case for describing many of the flows observed in our oceans, simply based on the Euler equation, with (piecewise) constant density and with suitable boundary conditions. The analyses start from the Euler and mass conservation equations, expressed in a rotating, spherical coordinate system (but the f -plane and β -plane approximations are also mentioned); five examples are discussed. For three of them, a suitable non-dimensionalization is introduced, and a single small parameter is identified in each case. These three examples lead straightforwardly and directly to new results for: waves on the Pacific Equatorial Undercurrent (EUC) with a thermocline (in the f -plane); a nonlinear, three-dimensional model for EUC-type flows (in the β -plane); and a detailed model for large gyres. The other two examples are exact solutions of the complete system: a flow which corresponds to the underlying structure of the Pacific EUC; and a flow based on the necessary requirement to use a non-conservative body force, which produces the type of flow observed in the Antarctic Circumpolar Current. (All these examples have been discussed in detail in the references cited.) This review concludes with a few comments on how these solutions can be extended and expanded. This article is part of the theme issue ‘Nonlinear water waves’.