Thermal versus mechanical topography: an experimental investigation in a rotating baroclinic annulus
Thermal versus mechanical topography: an experimental investigation in a rotating baroclinic annulus
复制标题
DOI：
10.1080/03091929.2019.1697875
复制
发表时间：
2020-02
影响因子：
1.3
通讯作者：
S. D. Marshall;P. Read
中科院分区：
文献类型：
--
作者：
S. D. Marshall;P. Read
我们提出了一系列实验研究，其中使用差热环空来研究地形对旋转分层流的影响。特别是，我们通过方位角变化的差异加热研究阻塞效应，并将其与之前使用部分机械屏障的实验进行比较。所使用的热地形由一块平坦的加热元件组成，覆盖底座的一小部分方位角，形成相当于部分屏障，以研究阻塞流和未阻塞流之间的差异。尽管没有物理障碍或底部捕获波的形成，但这些方位变化的加热实验产生的结果与我们之前使用机械屏障的实验有许多相似之处。特别是，当漂移流和地形在低泰勒数时以“干扰”状态相互作用，但在较高泰勒数时形成不稳定的“不规则”状态时，发现了独特的流动结构。这表明粘连可能是由热或机械不均匀性之一或两者引起的。在这两种实验中都注意到了相干/持续共振三元波的证据，尽管发现三元波的分量波数及其对流动的影响取决于所讨论的地形。
We present a series of experimental investigations in which a differentially-heated annulus was used to investigate the effects of topography on rotating, stratified flows. In particular, we investigate blocking effects via azimuthally varying differential-heating and compare them to previous experiments utilising partial mechanical barriers. The thermal topography used consisted of a flat patch of heating elements covering a small azimuthal extent of the base, forming an equivalent of a partial barrier, to study the difference between blocked and unblocked flow. These azimuthally-varying heating experiments produced results with many similarities to our previous experiments with a mechanical barrier, despite the lack of a physical obstacle or formation of bottom-trapped waves. In particular, a unique flow structure was found when the drifting flow and the topography interacted in the form of an “interference” regime at low Taylor number, but forming an erratic “irregular” regime at higher Taylor number. This suggests that blocking may be induced by either or both of a thermal or mechanical inhomogeneity. Evidence of coherent/persistent resonant wave triads was noted in both kinds of experiment, though the component wavenumbers of the wave-triads and their impact on the flow was found to depend on the topography in question.