Effect of Dispersion on Solutal Convection in Porous Media
Effect of Dispersion on Solutal Convection in Porous Media
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DOI：
10.1029/2018gl079849
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发表时间：
2018-09
影响因子：
5.2
通讯作者：
Yuehua Liang;Baole Wen;M. Hesse;D. DiCarlo
中科院分区：
文献类型：
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作者：
Yuehua Liang;Baole Wen;M. Hesse;D. DiCarlo
多孔介质中的溶质对流被认为是由分子瑞利数Ram控制的，Ram是浮力驱动力与扩散耗散的比值。质量通量应随Ram线性增加，指间距应随Ram-1/2减小。相反，我们的实验发现，通量水平在大拉姆和手指间距增加拉姆。在这里，我们表明，对流模式是由分散的瑞利数，拉德，平衡浮力和分散控制。增加多孔介质的珠粒尺寸增加Ram，但降低Rad，因此使图案粗糙化。虽然通量主要由Ram控制，但机械分散的各向异性导致图案的不对称性，这限制了大珠尺寸下的通量。
Solutal convection in porous media is thought to be controlled by the molecular Rayleigh number, Ram, the ratio of the buoyant driving force over diffusive dissipation. The mass flux should increase linearly with Ram and the finger spacing should decrease as Ram−1/2 . Instead, our experiments find that flux levels off at large Ram and finger spacing increases with Ram. Here we show that the convective pattern is controlled by a dispersive Rayleigh number, Rad, balancing buoyancy and dispersion. Increasing the bead size of the porous medium increases Ram but decreases Rad and hence coarsens the pattern. While the flux is predominantly controlled by Ram, the anisotropy of mechanical dispersion leads to an asymmetry in the pattern that limits the flux at large bead sizes.