摘要:

The adjustment of a nonlinear, quasigeostrophic, stratified ocean to an impulsively applied wind stress is investigated under the assumption that barotropic advection of vortex tube length is the most important nonlinearity. The present study complements the steady state theories which have recently appeared, and extends earlier, dissipationless, linear models.

ISSN:0309-1929    

DOI:10.1080/03091928408222849

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Ray calculations are used to examine short-wave propagation through an inertial current. The results exhibit differences from theories of short-wave refraction based on steady shears. Caustics take the place of critical layers as the locations of ray focusings and form for short waves at all intrinsic frequencies and at all phases of the inertial oscillation. Conversely, short waves that refract to, and remain at, high vertical wavenumber can escape instability altogether.

ISSN:0309-1929    

DOI:10.1080/03091928408222850

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

In part I of this study (Fearn, 1983b), instabilities of a conducting fluid driven by a toroidal magnetic field B were investigated. As well as confirming the results of a local stability analysis by Acheson (1983), a new resistive mode of instability was found. Here we investigate this mode in more detail and show that instability exists whenB(s) has a zero at some radiuss=sc. Then (in the limit of small resistivity) the instability is concentrated in a critical layer centered onsc. The importance of the region whereBis small casts some doubt on the validity of the simplifications made to the momentum equation in I. Calculations were therefore repeated using the full momentum equation. These demonstrate that the neglect of viscous and inertial terms when the mean field is strong does not lead to spurious results even when there are regions whereBis small.

ISSN:0309-1929    

DOI:10.1080/03091928408222851

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

It is shown that the frozen-in magnetic field in a given random homogeneous flow of an incompressible fluid which is renewed after a finite characteristic time grows exponentially. The rate-of-growth is positive in the limit of small magnetic diffusivity and continuous invm. The increase of the rates-of-growth for successive field moments is revealed by the intermittent distribution of the magnetic field generated.

ISSN:0309-1929    

DOI:10.1080/03091928408222852

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor