A turbulent equatorial jet
- 1 November 1961
- journal article
- research article
- Published by Cambridge University Press (CUP) in Journal of Fluid Mechanics
- Vol. 11 (03) , 465-477
- https://doi.org/10.1017/s0022112061000664
Abstract
A recent study of a laminar jet in a rotating spherical shell of fluid is extended to the case of a turbulent planetary jet at the equator of a rotating, stratified atmosphere or ocean. General forms of the velocity, density and pressure functions of both the mean motion and the turbulence are derived by a dimensional analysis applied to the mean and perturbation equations. The horizontal and vertical dimensions are estimated, based on the three characteristic constants of the problem, which are the momentum transfer, the stability and a rotation parameter. The estimates are in good agreement with the dimensions of the Cromwell current, i.e. the equatorial undercurrent of the Pacific Ocean.To the first order of approximation, the mean axial velocity in the theory is independent of distance along the jet axis. The mean horizontal transverse velocity component is much smaller and decreases upstream. The mean vertical velocity is extremely small, also decreasing upstream. The two horizontal velocity components of the turbulence are of the same order and, in the undercurrent, are about one-fourth the mean axial velocity. The vertical turbulent component is much smaller. Finally, it is shown that the eddy-viscosity concept is inappropriate for this problem because at least one of the eddy coefficients would have to be negative.Keywords
This publication has 8 references indexed in Scilit:
- An approximate theoretical analysis of the equatorial undercurrentDeep Sea Research (1953), 1960
- Measurements of the Cromwell currentDeep Sea Research (1953), 1960
- A laminar planetary jetJournal of Fluid Mechanics, 1960
- Dynamical Computation of the Equatorial Current System of the Pacific, with Special Application to the Equatorial UndercurrentGeophysical Journal International, 1958
- Observations of the Pacific Equatorial UndercurrentNature, 1958
- The Equatorial Undercurrent in the Light of the Vorticity EquationTellus A: Dynamic Meteorology and Oceanography, 1955
- Equatorial Undercurrent in Pacific Ocean Revealed by New MethodsScience, 1954
- The Atmospheres of the Other PlanetsPublished by Springer Nature ,1951