Numerical nonlinear analysis of subcritical Rayleigh-Bénard convection in a horizontal confined enclosure filled with non-Newtonian fluids
Numerical nonlinear analysis of subcritical Rayleigh-Bénard convection in a horizontal confined enclosure filled with non-Newtonian fluids
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充满非牛顿流体的水平受限外壳中亚临界瑞利-贝纳德对流的数值非线性分析
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
N. Messaoudene
中科院分区：
文献类型：
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作者：
Ouahiba Benouared;M. Mamou;N. Messaoudene
采用刚性边界条件，数值研究了Rayleigh-Benard位形中的非牛顿亚临界对流。的流动配置包括一个有限的纵横比外壳受到垂直温度梯度，这是建立通过加热和冷却的下壁和上壁通过恒定的热通量或通过施加恒定的温度。使用Carreau-Yasuda模型对非牛顿流体粘度进行建模。对流由守恒方程控制，并采用具有时间精确格式的有限差分法进行数值求解。对于一个浅封闭，当壁受到恒定的热通量，渐近解推导出假设平行流的行为。数值和渐近解之间的比较进行。讨论了控制参数，即瑞利数和普朗特数以及流体流变参数对亚临界对流开始的影响。
Non-Newtonian subcritical convection in a Rayleigh-Benard configuration was investigated numerically, using rigid boundary conditions. The flow configuration consisted of a finite aspect ratio enclosure subject to a vertical temperature gradient, which was established by heating and cooling the lower and the upper walls by either a constant heat flux or by applying constant temperatures. The non-Newtonian fluid viscosity was modeled using the Carreau-Yasuda model. The convective flow was governed by the conservation equations, which were solved numerically using a finite difference method with a time-accurate scheme. For a shallow enclosure, when the walls were subject to constant heat fluxes, an asymptotic solution was derived assuming a parallel flow behavior. A comparison between the numerical and asymptotic solutions was performed. The effects of the controlling parameters, namely, the Rayleigh and the Prandtl numbers, and the fluid rheological parameters on the onset of subcritical convective flow we...