Two-component convection flow driven by a heat-releasing concentration field
Two-component convection flow driven by a heat-releasing concentration field
复制标题
放热集中场驱动的二分量对流
DOI：
10.1017/jfm.2021.715
复制
发表时间：
2021-10
影响因子：
3.7
通讯作者：
Yantao Yang
中科院分区：
文献类型：
--
作者：
Yuhang Du;Mengqi Zhang;Yantao Yang
摘要本文研究了由放热浓度场驱动的对流，该浓度场本身是稳定分层的。放热速率与浓度成线性关系。线性稳定性分析进行，以确定临界放热速率为给定的流体性质和浓度差。与临界放热速率相关的最不稳定模式对于大浓度瑞利数（即无量纲浓度差）和大施密特数（即浓度组分的粘度与扩散率之比）可以是振荡的。充分发展的流动，然后调查直接数值模拟。底板附近的流动结构比顶板附近的流动结构具有更大的水平尺度。体积中的浓度几乎是恒定的，并且对于所有探索的参数取类似的值，这导致对流通量随高度线性增加。为了解释全局输运性质的依赖性，我们将Rayleigh-Bénard对流的统一理论扩展到当前系统，并发展了全局通量的标度律。理论模型可以准确地描述数值结果。
Abstract In this work we study the convection flow driven by a heat-releasing concentration field which itself is stably stratified. The heat-releasing rate is linearly proportional to concentration. Linear stability analysis is conducted to determine the critical heat-releasing rate for given fluid properties and concentration differences. The most unstable mode associated with the critical heat-releasing rate can be oscillatory for a large concentration Rayleigh number, i.e. the non-dimensionalized concentration difference and large Schmidt number, i.e. the ratio of viscosity to diffusivity of the concentration component. Fully developed flows are then investigated by direct numerical simulations. Flow structures near the bottom plate have larger horizontal scales than those near the top plate. The concentration in the bulk is almost constant and takes a similar value for all the explored parameters, which results in the convective flux increasing linearly with height. To explain the dependences of the global transport properties, we extend the unifying theory of the Rayleigh–Bénard convection to the current system and develop scaling laws for the global fluxes. The numerical results can be described accurately by the theoretical model.
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