水平流动作用下的纯流体Rayleigh-Benard对流时空结构

Rayleigh-Benard convection in single fluid with lateral flows

通过二维流体力学基本方程组的数值模拟,研究了普朗特数Pr=1.0时矩形渠槽中水平流动作用下的纯流体Rayleigh-Benard对流时空结构的影响,并与Pr=6.99时的结果进行了比较。结果表明:当水平流动雷诺数Re=0时,定常对流的波数随着瑞利数的增加而变大;对于相对瑞利数r=3.0的情况,当Re<40时,获得了行波对流结构,当40≤Re≤75时,出现了局部行波对流结构;在局部行波对流存在的范围内,随着雷诺数的增加或瑞利数的减小,局部行波对流的存在宽度减小;当Pr从6.99减小到1.0时,局部行波对流的Re依赖范围将由9≤Re≤18变成40≤Re≤75。

By using a two-dimensional numerical simulation of the fully hydrodynamic equations, the influence of lateral flows on the spatio-temporal structure of Rayleigh-Benard convection in single fluid in a rectangular channel at Prandtl number Pr=1.0is studied, and is compared with the result of Pr=6.99. For the Reynolds number Re=0, the wave number of the stationary overturning convection increases with increasing Rayleigh number Ra. While the Reynolds number Re<40 at reduced Rayleigh number r=3.0, the traveling wave convection structure is obtained. If the Reynolds number 40≤Re≤75 at r=3.0, a kind of localized traveling wave convection structure is found. With increasing the Reynolds number or decreasing reduced Rayleigh number in the range of existence of localized traveling wave convection, the width of localized traveling wave convection decreases. When Pr decreases from 6.99 to 1.0,the Re dependence range of localized traveling wave convection changes from 9≤Re≤18 to 40≤Re≤75.