摘要:

The onset of shear instability in a stably stratified, radiating star is examined. The stability of a particular shear layer is studied numerically, and a criterion for the onset of instability is proposed.

ISSN:0309-1929    

DOI:10.1080/03091927708240377

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The scattering of energy from coherent internal tide modes into small scale internal waves in an ocean with a random rough bottom is investigated. Such scattering results in a decay of energy in the coherent internal tide characterized by a length scale of roughly 6 |MX 103km or about 50 wavelengths for the first mode for conditions representative of the Northeast Pacific. This rate of dissipation appears to be comparable to that characteristic of other dissipative processes such as resonant interactions with the background internal wave spectrum and eddy friction due to small scale turbulence.

ISSN:0309-1929    

DOI:10.1080/03091927708240378

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

A method is described for the asymptotic study of natural convection problems in the limit of fast flow, when the dimensionless Rayleigh numberRtends to infinity. The Boussinesq approximation is used, and attention is confined to a viscous limit, with the Prandtl number taken as infinite; this makes the fluid momentum negligible. The flow is nevertheless so fast that the temperature is disturbed only in thin layers. The heat equation is studied in these layers, and the effect of the buoyancy in the layers on the motion is expressed in terms of the heat flux.

ISSN:0309-1929    

DOI:10.1080/03091927708240379

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The vorticity field induced by a topography in a homogeneous rotating fluid bounded by a free-surface is investigated. It is found that the integrated strength of the topographically bound vortex is zero and that the volume of the free-surface perturbations is equal to the volume of the topography.

ISSN:0309-1929    

DOI:10.1080/03091927708240380

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Edited by Sir Harold Jeffreys and Bertha Swirles (Lady Jeffreys). Gordon and Breach Science Publishers, London, Paris, New York, xviii + 493 pages.

ISSN:0309-1929    

DOI:10.1080/03091927708240381

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

ISSN:0309-1929    

DOI:10.1080/03091927708240382

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Application of statistical estimators to analysis and prediction is examined from the point of view of geophysical fluid dynamics. The fundamental difficulty is that estimators constructed from observational records of limited length (the usual case in GFD) are sensitive to sampling errors in the statistics upon which they are based. To achieve meaningful results, the number of data, or input, parameters must be limited. The relationship between statistical and dynamical models (particularly clear for linear systems) coupled with certain statistical methods are explored with respect to the problem of input parameter selection, both for linear and nonlinear systems. Methods of assessing the effects of sampling errors in hindcasts are discussed and techniques for minimizing these effects in forecasts are evaluated. A method of efficiently condensing statistical models to a few input parameters and transfer functions is given. Finally the steps of hindcast analysis and forecaster construction are discussed from the practical point of view.

ISSN:0309-1929    

DOI:10.1080/03091927708240383

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The dependence of inertial oscillation frequency on time since a cylindrical container began rotating from rest is established experimentally for several axially symmetric modes of oscillation. The oscillations were excited by including a sinusoidal perturbation in the rotation speed of the container which served to establish an exchange of fluid between the viscous boundary layers and the interior. The interior is set into oscillation by the boundary layer flow and the resulting axial pressure differences are used to establish the amplitude of the inertial oscillation. The best agreement between our experiments and the theoretical work by Lynn (1973) on the time dependence of inertial oscillation frequency occurs for the lowest frequency modes. From a limited study on amplitude of the inertial oscillations it appears that the growth rate of these disturbance is such thate−1of the ultimate amplitude is achieved after one and a hall spin-up times from the time that the container is switched on. No non-linear effects in perturbation amplitude for the dependence of inertial oscillation frequency on time were found for the amplitudes used in these experiments

ISSN:0309-1929    

DOI:10.1080/03091927708240384

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Taylor's analysis of the reflection of a Kelvin wave by the perpendicular end wall of a rotating channel is extended to the case of an arbitrary end wall. A mirror imaging theorem applicable to such situations is derived.

ISSN:0309-1929    

DOI:10.1080/03091927708240385

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The kinematic dynamo problem is considered for certain steady velocity fields with symmetries that are plausible in a rapidly rotating convective system. By generalizing results proved for the mean field dynamo model by Proctor (1977a), it is shown that for a related “comparison problem” with modified boundary conditions, the eigenvalues are degenerate if there is no axisymmetric mean circulation, with modes of dipole and quadrupole parity excited with equal ease. The comparison problem can be shown to be closely similar to the dynamo problem when there is a region unfavourable to dynamo action surrounding the dynamo region. The near-symmetries found by Roberts (1972) for the mean field model are invoked to suggest that a close correspondence is likely even when this region is absent. It is therefore conjectured that such mean motions may be important in explaining the observed preference for solutions of dipole parity by planetary dynamos.

ISSN:0309-1929    

DOI:10.1080/03091927708240386

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor