Planforms in Thermal Convection With Internal Heat Sources at Large Rayleigh and Prandtl Numbers
Planforms in Thermal Convection With Internal Heat Sources at Large Rayleigh and Prandtl Numbers
复制标题
大瑞利数和普朗特数下内部热源的热对流平面
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
P. Olson
中科院分区：
文献类型：
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作者：
S. Weinstein;P. Olson
实验室实验被用来检查大量的内部热量产生的影响，在一个恒定的粘度，高普朗特数流体的瑞利-贝纳德对流平面形状。内部发热是通过以恒定速率降低边界温度来模拟的。基于所施加的温差的瑞利数（RaT）为1.5 ×105，基于内部发热量的瑞利数（RaH）在0至3.0×106之间变化。在没有内部热量产生的对流平面形状是对称的辐条模式，其中连接的辐条的上升和下降流平均具有相等的强度。由于内部产生热量，平面形状是不对称的，浮力集中在孤立的下降弧形沟槽和圆形羽流中。上升板块是非浮力的，尽管它们的平面形状比下降板块连接得更紧密。观察到的时间依赖性的量增加与内部发热，并发生分支和传播的负浮力沟槽。
Laboratory experiments are used to examine the effects of large amounts of internal heat generation on Rayleigh-Benard convection planforms in a constant viscosity, high Prandtl number fluid. Internal heat generation is simulated by lowering the boundary temperatures at a constant rate. The Rayleigh number (RaT) based on the imposed temperature difference is l.5×105 and the Rayleigh number based on the amount of internal heat generation (RaH) is varied from 0 to 3.0×106. In the absence of internal heat generation the convection planforms are the symmetric spoke pattern in which connected spokes of ascending and descending flow have, on average, equal strength. With internal heat production, the planform is asymmetric with buoyancy concentrated in isolated descending arcuate trenches and circular plumes. The upwellings are nonbuoyant, although their planform is more connected than downwellings. The amount of time dependence is observed to increase with internal heat generation, and occurs by branching and propagation of the negatively buoyant trenches.