Diffusive destabilisation of the baroclinic circular vortex
Diffusive destabilisation of the baroclinic circular vortex
复制标题
DOI：
10.1080/03091927009365767
复制
发表时间：
1970-04
影响因子：
1.3
通讯作者：
M. McIntyre
中科院分区：
文献类型：
--
作者：
M. McIntyre
结果表明，即使在动量和热量扩散系数为零的情况下，旋转分层纬向剪切流对纬向对称扰动的不稳定性也比经典的无粘绝热判据所表示的更不稳定，除非普朗特数σ=1。其中既有单调不稳定性，又有增长的振荡(“超稳定”)，前者决定了稳定性判据，具有较高的增长率。σ与1相差越大，参数空间中按经典判据流动稳定但实际上不稳定的区域就越大。如果斜压性足够大，使得经典判据也表明不稳定性，则相应的无粘绝热模通常具有最高的数值增长率。一个例外是小等温线斜率和小σ的情况。线性化理论的单个简正波在形式上也是有限幅值解，但没有从理论上评估有限幅值解的影响。
Abstract It is shown that, even for vanishingly small diffusivities of momentum and heat, a rotating stratified zonal shear flow is more unstable to zonally symmetric disturbances than would be indicated by the classical inviscid adiabatic criterion, unless σ, the Prandtl number, = 1. Both monotonic instability, and growing oscillations ("overstability") are involved, the former determining the stability criterion and having the higher growth rates. The more σ differs from 1, the larger the region in parameter space for which the flow is stable by the classical criterion, but actually unstable. If the baroclinity is sufficiently great for the classical criterion also to indicate instability, the corresponding inviscid adiabatic modes usually have the numerically highest growth rates. An exception is the case of small isotherm slope and small σ. A single normal mode of the linearized theory is also, formally, a finite amplitude solution; however, no theoretical attempt is made to assess the effect of finit...