Analytical and Experimental Study of Instabilities in Buoyancy-Driven Convection in Porous Media

在物理化学科学的现代技术应用中，两相无序介质是最常见的。这种介质的一个常见例子是由分散在固体多孔介质中的流体相组成的非均相混合物。这项研究的任务是研究两类完全饱和系统中与浮力驱动对流相关的热不稳定现象：(I)饱和纯流体的多孔介质和(Ii)饱和二元流体的多孔介质。我们提出了一个严格的分析和实验程序来研究充满多孔介质的大长宽比封闭空间中自然对流过程中的图案形成。我们的主要目标是：(1)描述对流流动的各种稳定区域，并探索二次不稳定开始后的对流状态；(2)发展新的实验技术，包括无创磁共振成像，用于高精度测量和确定多孔介质中的流动模式，以及(3)多孔介质中自然对流宏观控制方程的验证。

Two-phase disordered media are most frequently encountered in modern technological applications of the physical and chemical sciences. A common example of such media is heterogeneous mixtures consisting of a fluid phase dispersed in a solid porous medium. The mission of the proposed research is to study thermal instability phenomena associated with buoyancy- driven convection in two classes of fully-saturated systems: (i) porous media saturated with pure fluids, and (ii) porous media saturated with binary fluids. We propose a rigorous analytical and experimental program to investigate pattern formation during natural convection in large aspect ratio enclosures filled with porous media. Our primary objectives are: (1) the delineation of the various stability domains for the convective flows and an exploration of the convective states after the onset of secondary instabilities, (2) the development of novel experimental techniques, including non- invasive magnetic resonance imaging, for high precision measurements and determining the flow patterns in porous media, and (3) the validation of macroscopic governing equations for natural convection in porous media.