On the transition between axisymmetric and non-axisymmetric flow in a rotating liquid annulus subject to a horizontal temperature gradient: Hysteresis effects at moderate Taylor number and baroclinic waves beyond the eady cut-off at high Taylor number
作者:
R. Hide,
P.J. Mason,
期刊:
Geophysical & Astrophysical Fluid Dynamics
(Taylor Available online 1978)
卷期:
Volume 10,
issue 1
页码: 121-156
ISSN:0309-1929
年代: 1978
DOI:10.1080/03091927808242634
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The transition between axisymmetric and non-axisymmetric régimes of flow in a rotating annulus of liquid subject to horizontal temperature gradient is known from previous experimental studies to depend largely on two dimensionless parameters. These are Θ, which is proportional to the impressed density contrast Δρ and inversely proportional to the square of the angular speed of rotation ω, and 𝒯 (Taylor number), which is proportional to ω2/v2where v is the coefficient of kinematic viscosity. At moderate values of 𝒯, around 107, the critical value of Θ above which axisymmetric flow is found to OCCUT and below which non-axisymmetric fully-developed baroclinic waves (sloping convection) occur, is fairly insensitive to 𝒯. Though sharp, the transition exhibits marked hysteresis when the upper surface of the liquid is free (but not when the upper surface is in contact with a rigid lid), and it is argued on the basis of the experimental evidence supported by various results of baroclinic instability theory that both the sharpness of the transition and the hysteresis phenomenon are consequences of the combined effects of potential vorticity gradients and viscosity on the process of sloping convection.
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