Convective shutdown in a porous medium at high Rayleigh number
Convective shutdown in a porous medium at high Rayleigh number
复制标题
高瑞利数多孔介质中的对流关闭
DOI：
10.1017/jfm.2013.23
复制
发表时间：
2013
影响因子：
3.7
通讯作者：
J. Lister
中科院分区：
文献类型：
--
作者：
D. Hewitt;J. Neufeld;J. Lister
摘要在封闭区域内，由沿上边界沿着的稠密浮力源驱动的对流，由于平均内部密度的增加，很快开始减弱。在本文中，理论和数值模型开发的随后长时间的关闭在一个二维多孔介质中的对流在高瑞利数$\mathit{Ra}$。本文件的目的有两个。首先，这个缓慢发展的“单边”关闭系统和统计稳定的“双边”Rayleigh-Bénard（RB）细胞之间的关系进行了研究。RB细胞的努塞尔数$\mathit{Nu}$的数值测量（休伊特等人，物理修订信函：vol. 108，2012，224503）通过简单的参数化$\mathit{Nu}= 2很好地描述。75+ 0。0069\mathit{Ra}$ .这种参数化是用于理论箱模型的单侧关机系统，并发现该系统的高分辨率数值模拟提供了很好的协议。关机的动态结构也可以通过RB单元的测量准确地预测。结果给出了一个一般的幂律状态方程。其次，这些想法被扩展到模拟更复杂的物理系统，其中包括两个流体层的状态方程，使得在（移动）界面处形成的解决方案比任何一层都更密集。这两种流体是不混溶的或可混溶的。在流体之间的平界面的情况下，理论箱模型与数值模拟比较好。Hele-Shaw小室实验和数值模拟结果均表明，界面变形能显著增强对流通量。这些结果的适用性地质封存的${\mathrm{CO} }_{2} $在盐水层的对流溶解进行了讨论。
Abstract Convection in a closed domain driven by a dense buoyancy source along the upper boundary soon starts to wane owing to the increase of the average interior density. In this paper, theoretical and numerical models are developed of the subsequent long period of shutdown of convection in a two-dimensional porous medium at high Rayleigh number $\mathit{Ra}$ . The aims of this paper are twofold. Firstly, the relationship between this slowly evolving ‘one-sided’ shutdown system and the statistically steady ‘two-sided’ Rayleigh–Bénard (RB) cell is investigated. Numerical measurements of the Nusselt number $\mathit{Nu}$ from an RB cell (Hewitt et al., Phys. Rev. Lett., vol. 108, 2012, 224503) are very well described by the simple parametrization $\mathit{Nu}= 2. 75+ 0. 0069\mathit{Ra}$ . This parametrization is used in theoretical box models of the one-sided shutdown system and found to give excellent agreement with high-resolution numerical simulations of this system. The dynamical structure of shutdown can also be accurately predicted by measurements from an RB cell. Results are presented for a general power-law equation of state. Secondly, these ideas are extended to model more complex physical systems, which comprise two fluid layers with an equation of state such that the solution that forms at the (moving) interface is more dense than either layer. The two fluids are either immiscible or miscible. Theoretical box models compare well with numerical simulations in the case of a flat interface between the fluids. Experimental results from a Hele-Shaw cell and numerical simulations both show that interfacial deformation can dramatically enhance the convective flux. The applicability of these results to the convective dissolution of geologically sequestered ${\mathrm{CO} }_{2} $ in a saline aquifer is discussed.
影响因子：
64.8
作者：
Gilfillan, Stuart M. V.;Lollar, Barbara Sherwood;Ballentine, Chris J.
通讯作者：
Ballentine, Chris J.
影响因子：
5.2
作者：
Neufeld, Jerome A.;Hesse, Marc A.;Huppert, Herbert E.
通讯作者：
Huppert, Herbert E.
影响因子：
3.7
作者：
D. Vella;J. Neufeld;H. Huppert;J. Lister
通讯作者：
D. Vella;J. Neufeld;H. Huppert;J. Lister