Discrete transitions in turbulent convection
Discrete transitions in turbulent convection
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湍流对流中的离散转变
DOI：
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发表时间：
1954
期刊：
影响因子：
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通讯作者：
W. Malkus
中科院分区：
文献类型：
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作者：
W. Malkus
流体中水平导热表面之间的对流是热湍流的一个非常简单的例子，因为平均热输运与位置无关，而这些表面之间的距离是唯一的几何参数。本文测量了瑞利数为1010的对流中的热输运和平均速度。在瑞利数为1700时和1000000之间观察到热传递曲线的斜率有六个离散转变。虽然从流体边界到中间区域的温度梯度变化了一个数量级，但这些转变似乎与基于恒定温度梯度的假设所推导的转变一致。文中还报道了脉动速度场的各种目视观测结果。流体中附加的竖直障碍物对水平流动有明显影响，但对热传递影响不大。与给定的热传输相关的流动模式的这种明显的缺乏唯一性表明了一种新的方法来研究湍流现象，在下面的理论论文中讨论。
The convection in a fluid between horizontal conducting surfaces is a very simple example of thermal turbulence, for the mean heat transport is independent of position while the distance between these surfaces is the only geometric parameter. This paper describes measurements of the heat transport and mean velocity in such convection up to Rayleigh numbers of 1010. Six discrete transitions in the slope of the heat-transport curve were observed between Rayleigh numbers of 1700 and 1000000. Although the thermal gradients vary by an order of magnitude from a boundary to the mid-regions of the fluid, these transitions appear to agree with those deduced on an assumption of a constant thermal gradient. Various visual observations of the fluctuating velocity field are also reported. Additional vertical barriers in the fluid markedly influence the horizontal flow but have negligible effect on the heat transport. This apparent lack of uniqueness of the flow patterns associated with a given heat transport suggests a new approach to turbulent phenomena discussed in a following theoretical paper.