论文标题
中性稳定剪切层中的波相互作用：常规和单数模式，非模式生长
Wave interactions in neutrally stable shear layers: regular and singular modes, and non-modal growth
论文作者
论文摘要
在最近的字母中，Carpenter和Guha（2019）比较了光滑的二维剪切曲线的中性模式，而没有拐点与其相应的分段线性轮廓的模式相比。平滑轮廓中的常规模式被确定为对数值分辨率最少敏感的模式，而单数模式显示出高灵敏度。在这里，我们使用波浪相互作用方法提供了物理解释，以了解常规模式和单数模式的结构和行为。常规模式是位于剪切曲线的浓缩平均涡度梯度的界面rossby波。相反，奇异模式是由单一旋转涡流干扰之间的一种单向锁定相互作用产生的，该相互作用是由剖面不同水平的平均流动和界面的rossby波被动地推动的。我们表明，这种一种方式相互作用也可以导致界面rossby波的持续非模式生长，而标准特征值分析无法捕获。
In a recent letter, Carpenter and Guha (2019) compared the neutral modes of a smooth two dimensional shear profile without an inflection point to the modes of its corresponding piecewise-linear profile. The regular mode in the smooth profile was identified as the one least sensitive to the numerical resolution, while the singular modes displayed high sensitivity. Here we provide a physical interpretation using a wave interaction approach for understanding the structure and behavior of both the regular and singular modes. The regular modes are the interfacial Rossby waves located at the concentrated mean vorticity gradient of the shear profile. In contrast, the singular modes result from a one way phase-locking interaction between singular vorticity disturbances, passively advected by the mean flow at different levels of the profile, and the interfacial Rossby waves. We show that this one way interaction can also lead to a sustained non-modal growth of the interfacial Rossby waves that cannot be captured by standard eigenvalue analysis.
