The response of surface buoyancy flux-driven convection to localized mechanical forcing
The response of surface buoyancy flux-driven convection to localized mechanical forcing
复制标题
表面浮力通量驱动对流对局部机械力的响应
DOI：
10.1007/s00348-019-2722-5
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发表时间：
2019
影响因子：
2.4
通讯作者：
Llewellyn Smith, Stefan G.
中科院分区：
文献类型：
--
作者：
Matusik, Katarzyna E.;Llewellyn Smith, Stefan G.
我们介绍了在装满淡水的矩形水箱表面同时施加浮力和机械作用力的实验室实验。浮力强迫是由表面的咸水源驱动沿一端壁下沉的半线羽流产生的，而机械强迫是由持续流动的淡水穿过储罐表面产生的。当烟羽的盐平流与通过上边界的盐的扩散相匹配时，就实现了稳定的环流。表面应力驱动着与羽流方向相同的流动，导致了一个对流单体，其深度由两种作用力的相互作用决定。当表面应力相对较弱时，稳态流动可用水平对流的高瑞利数‘回收箱’模型来描述(Hughes等人。摘自《流体力学》581：251-276,2007)。一旦压力大到足以颠覆分层水域，就会形成局部混合区域。这种区域湍流的直接后果是以更新鲜的水的形式将稳定的浮力净输入到羽流中，使其太弱而无法穿透到底部边界。一般来说，羽流不能在实验时间范围内恢复全深度环流。由此产生的流动可以用回收箱模型来描述，该模型具有空间变化的湍流扩散系数，该扩散系数由混合区中发展的湍流涡流的特征来参数。这项工作应用实验技术表明，在适当的机械强迫下，浮力驱动的环流将发展局部混合，在相对较长的时间尺度上显著改变环流的整体结构和密度分布。实验结果证实了回收箱模型是描述此类系统流动结构的有效参数。
We present laboratory experiments in which both a buoyancy and mechanical forcing are imposed on the surface of a rectangular tank filled with freshwater. The buoyancy forcing is generated by a saltwater source at the surface that drives a sinking half-line plume along one endwall, and the mechanical forcing is generated by a continuous flow of freshwater across the surface of the tank. A steady-state circulation is achieved when the advection of salt by the plume is matched by the diffusion of salt through the upper boundary. The surface stress drives flow in the same direction as the plume, resulting in a convective cell whose depth is determined by the interplay of the two forcings. When the surface stress is relatively weak, the steady-state flow is described by a high-Rayleigh number ‘recycling box’ model for horizontal convection (Hughes et al. in J Fluid Mech 581:251–276, 2007). Once the stress is strong enough to overturn the stratified waters, a region of localized mixing develops. The immediate consequence of this regional turbulence is a net input of stabilizing buoyancy in the form of fresher water into the plume, which renders it too weak to penetrate to the bottom boundary. In general, the plume is unable to recover a full-depth circulation within the experiment time frame. The resulting flow can be described by the recycling box model with a spatially varying turbulent diffusivity parameterized by the characteristics of the turbulent eddy that develops in the mixing region. This work applies experimental techniques to show that, with adequate mechanical forcing, a buoyancy-driven circulation will develop localized mixing that significantly alters the overall structure and density distribution of the circulation for relatively long timescales. The experimental results corroborate the recycling box model as a valid descriptor of the flow structure in such systems.
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影响因子：
3.7
作者：
J. Hazewinkel;F. Paparella;W. Young
通讯作者：
W. Young
经向翻转环流的调节及其对混合深度的依赖性
DOI：
--
发表时间：
2016
期刊：
影响因子：
--
作者：
C. Vreugdenhil;A. Hogg;R. W. Griffiths;G. Hughes
通讯作者：
G. Hughes
密斜层的对流形成：实验室实验
DOI：
--
发表时间：
1996
期刊：
影响因子：
--
作者：
D. Pierce;P. Rhines
通讯作者：
P. Rhines
影响因子：
3.7
作者：
BAINES, WD;TURNER, JS
通讯作者：
TURNER, JS
影响因子：
0.5
作者：
Dewar, W. K.;Bingham, R. J.;Wiebe, P. H.
通讯作者：
Wiebe, P. H.