Mean wind in convective turbulence of mercury
Mean wind in convective turbulence of mercury
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DOI：
10.1103/physrevlett.94.034501
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发表时间：
2005-01-28
影响因子：
8.6
通讯作者：
Sano, M
中科院分区：
文献类型：
--
作者：
Tsuji, Y;Mizuno, T;Sano, M
本文对汞的热湍流中的大尺度环流（通常称为“风”）进行了实验研究。利用超声测速仪直接测量了128个点的瞬时速度分布。在纵横比Gamma= 1，2的情况下观察到周期性的速度振荡，而在Gamma=0.5的情况下没有观察到。其峰值频率由f（c）与Ra（c）（gamma）成比例缩放，其中Ra是瑞利数，对于Gamma= 1，2，gamma（c）= 0.43，0.45。f（c）与风环流频率f（p）接近，且从对流单体底部到顶部的渡越时间具有相同的量级。在Gamma=1时，预计会出现一个单滚环流;然而，在Gamma=0.5时，在上下板附近可能会出现轴对称环形环，它们在Ra= 7 x10（10）时是稳定的。
The large-scale circulation, often called "wind," in the confined thermal turbulence of mercury is studied experimentally. The instantaneous velocity profile at 128 points is directly measured using ultrasonic velocimetry. The periodic velocity oscillation is observed in the case of the aspect-ratio Gamma=1,2 but not in Gamma=0.5. Its peak frequency is scaled by f(c)proportional toRa(c)(gamma), where Ra is the Rayleigh number and gamma(c)=0.43,0.45 for Gamma=1,2. f(c) is close to the wind circulation frequency f(p), and has the same order of transit time from the bottom to the top of the convection cell. A single roll circulation is expected in Gamma=1; however, axisymmetric toroidal rings may exist near the upper and lower plate for Gamma=0.5, which are stable up to Ra=7x10(10).