On the instability of sheared disturbances
On the instability of sheared disturbances
复制标题
关于剪切扰动的不稳定性
DOI：
10.1017/s002211208700048x
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发表时间：
1987
影响因子：
3.7
通讯作者：
P. Haynes
中科院分区：
文献类型：
--
作者：
P. Haynes
在β平面上，常切变的无界流的小振幅扰动方程有一种特别简单的形式的众所周知的解。从物理角度来说，这样的解代表了一种流动，其中绝对涡度轮廓最初呈波浪形，但由于基本状态剪切而变形。在这里，它示出，至少在初始扰动具有长波长的情况下，涡度分布预测的解决方案最终成为正压不稳定的，因为剪切的物质轮廓导致局部逆转的绝对涡度的横流梯度。
The equation for small-amplitude disturbances to an unbounded flow of constant shear on a beta-plane has well-known solutions of a particularly simple form. In physical terms such solutions represent a flow in which absolute-vorticity contours, initially taking a wavy configuration, are deformed by the basic-state shear. Here it is shown that, at least in cases where the initial disturbance has long wavelength, the vorticity distribution predicted by such solutions eventually becomes barotropically unstable, as the shearing over of material contours leads to local reversals in the cross-stream gradient of absolute vorticity.