Observation of a link between energy dissipation rate and oscillation frequency of the large-scale circulation in dry and moist Rayleigh-Bénard turbulence
Observation of a link between energy dissipation rate and oscillation frequency of the large-scale circulation in dry and moist Rayleigh-Bénard turbulence
复制标题
干湿瑞利-贝纳德湍流中大尺度环流能量耗散率与振荡频率关系的观测
DOI：
10.1103/physrevfluids.3.083501
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发表时间：
2018
影响因子：
2.7
通讯作者：
R. Shaw
中科院分区：
文献类型：
--
作者：
D. Niedermeier;Kelken Chang;W. Cantrell;K. K. Chandrakar;D. Ciochetto;R. Shaw
在这项研究中，研究了湍流瑞利-贝纳德对流的小尺度和大尺度流动特性。使用室（纵横比）进行瑞利数范围和普朗特数的实验。此外，实验在干燥和潮湿条件下进行，即室的顶面和底面分别是干燥和潮湿的。对于潮湿条件，我们进一步区分存在和不存在氯化钠气溶胶颗粒的条件，如果达到过饱和条件，则会导致云滴形成。因此，我们分别将这些条件称为潮湿和多云。我们看到水蒸气的添加会影响湍流。在所有情况下，湍流动能耗散率随着温差的增加而增加，但湿对流和干对流的斜率不同。由于液态水含量低，我们没有观察到潮湿对流和阴对流之间存在明显差异。对于大尺度环流的特征振荡，观察到 Ra 也没有塌陷。我们观察到，对于所有考虑的条件，第一归一化特征振荡频率随着温差的增加而增加，即 Ra 的增加，但湿对流和干对流的斜率不同，湿对流和多云对流之间也没有明显差异。事实证明，除了单独的浮力效应之外，大范围环流的晃动或扭转模式以及湍流或能量耗散率似乎还受到相同机制的影响。这些观测结果提供了支持证据，表明大规模环流对相组成或界面物理不敏感，而仅取决于湍流的强度。
In this study both the small- and large-scale flow properties of turbulent Rayleigh-Bénard convection are investigated. Experiments are carried out using thechamber (aspect ratio) for Rayleigh number rangeand Prandtl number. Furthermore, experiments are run for dry and wet conditions, i.e., top and bottom surfaces of the chamber are dry and wet, respectively. For wet conditions we further distinguish between conditions with and without the presence of sodium chloride aerosol particles which, if supersaturated conditions are achieved, lead to cloud droplet formation. We therefore refer to these conditions as moist and cloudy, respectively. We see that the addition of water vapor influences the turbulent flow. In all cases, the turbulent kinetic energy dissipation rates increase with increasing temperature difference, but the slopes are different for wet and dry convection. We do not observe a clear difference between moist and cloudy convection due to low liquid water content. A similar lack of collapse with Ra is observed for the characteristic oscillations of the large-scale circulation. We observe that the first normalized characteristic oscillation frequency increased with increasing temperature difference, i.e., increasing Ra, for all conditions considered, but the slopes are different for wet and dry convection with again no clear difference between moist and cloudy convection. It turns out that the sloshing or torsional mode of the large-scale circulation and the turbulent flow or energy dissipation rate seem to be influenced by the same mechanism additional to the effect of buoyancy alone. These observational results provide supporting evidence that the large-scale circulation is insensitive to phase composition or interfacial physics and rather depends only on the strength of the turbulence.
影响因子：
2.7
作者：
Schumacher, Joerg;Bandaru, Vinodh;Scheel, Janet D.
通讯作者：
Scheel, Janet D.
影响因子：
3.7
作者：
Shi, Nan;Emran, Mohammad S.;Schumacher, Joerg
通讯作者：
Schumacher, Joerg