The effect of temperature-dependent viscosity and thermal conductivity on the onset of compressible convection
The effect of temperature-dependent viscosity and thermal conductivity on the onset of compressible convection
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DOI：
10.1080/03091929.2020.1777549
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发表时间：
2020-06
影响因子：
1.3
通讯作者：
Abrar A. Ali;L. Silvers
中科院分区：
文献类型：
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作者：
Abrar A. Ali;L. Silvers
导出了具有变输运系数的可压缩流体中热对流的线性方程组。对流的发生的标准，建立在线性稳定性分析的基础上，为一系列不同的热导率和粘度的温度依赖性的配置文件。研究表明，与温度相关的传输系数会导致比恒定传输系数更复杂的行为，并改变流体的稳定性条件。当瑞利数被定义在中层的物理性质和顶部的温度梯度保持不变，增加的热导率的温度依赖性被发现提高临界瑞利数显着，因为对流扰动，然后主要集中在该层的顶部。相反，对于粘度，确定了对稳定性的更微妙的影响。
The linear equations of thermal convection in a compressible fluid with non-constant transport coefficients are derived. The criterion for the onset of convection is established, based on linear stability analysis, for a range of different temperature-dependent profiles of thermal conductivity and viscosity. Temperature-dependent transport coefficients are shown to lead to a more complex behaviour than their constant counterparts, and modifies the stability condition of the fluid. When the Rayleigh number is defined in terms of the mid-layer physical properties and the temperature gradient at the top is held constant, increasing the temperature-dependence of thermal conductivity is found to raise the critical Rayleigh number dramatically, as the convective disturbance is then concentrated mainly at the top of the layer. In contrast, for viscosity a more subtle effect on stability is identified.