Thermal plumes in Rayleigh–Bénard convection have been observed to occur with strong vertical component of vorticity, resulting in spiraling hot updrafts and cold downdrafts. Results from two different simulations at Rayleigh numbers 9800 and 33 000 times the critical Rayleigh number close to the boundaries show rapid increase in the conditional averages of vertical velocity and temperature perturbation at large values of vertical vorticity. This result along with the spatial distribution of vertical vorticity indicates a strong correlation between narrow regions of upmoving hot fluid (or downmoving cold fluid) and local vertical vorticity. The horizontal dimension of these vortical plumes is an order of magnitude smaller than the layer depth, but they extend up to half the convective layer in the vertical direction.

中文翻译：

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湍流对流中热羽的涡流性质

Rayleigh–Bénard中的热羽 对流 已经观察到发生了强烈的垂直分量 涡度导致热气流上升和冷气流上升。在瑞利数为9800和33 000倍于接近边界的临界瑞利数的情况下，通过两次不同的模拟得出的结果表明，垂直速度的条件平均值和温度扰动在垂直值较大时迅速增加涡度。 该结果与垂直方向的空间分布 涡度 表示上升的热流体（或下降的冷流体）的狭窄区域与局部垂直区域之间的强相关性 涡度。 这些旋涡羽流的水平尺寸比层深小一个数量级，但它们在垂直方向上延伸到对流层的一半。