The displacement of a less viscous fluid by a more viscous fluid in a radial Hele-Shaw cell makes a circular pattern because the interface is hydrodynamically stable in this condition. Very recently, it has been experimentally reported that the hydrodynamically stable displacement in a partially miscible system induces fingering patterns while stable circular patterns are made at fully miscible and immiscible systems. The fingering instability in the partially miscible system results from complex and entangled elements involving viscous dissipation, molecular diffusion, and phase separation. The analyzing mechanism requires a quantitative relationship between the hydrodynamic interfacial fingering patterns and underlying physicochemical properties. Here, we experimentally investigated the change in fluid patterns formed by the progression of phase separation in the partially miscible systems and categorized them into three patterns: finger-like pattern, annular-like pattern, and circular pattern. Moreover, we propose the mechanism of the pattern formation by an interfacial tension measurement and evaluate the patterns by modified capillary number and newly defined body force ratio, . Our analysis revealed that the deformation index of the pattern can be expressed as a function of on a single curve regardless of the miscibility.

中文翻译：

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在径向Hele-Shaw流中由粘性耗散和相分离竞争控制的流体形态

在径向Hele-Shaw孔中，粘度较低的流体被粘度较高的流体取代的结构为圆形，因为在这种情况下界面在流体力学上是稳定的。最近，已经有实验报告说，在部分可混溶的系统中，流体力学稳定的位移会引起指状图样，而在完全可混溶和不可混溶的系统中会形成稳定的圆形图样。部分可混溶系统中的指法不稳定是由涉及粘性耗散，分子扩散和相分离的复杂且纠缠的元素造成的。分析机制要求流体动力界面指法模式与基础物理化学性质之间存在定量关系。这里，我们通过实验研究了部分可混溶系统中由相分离的进行而形成的流体模式的变化，并将其分为三种模式：手指状，环形和圆形。此外，我们提出了通过界面张力测量形成图案的机理，并通过修改的毛细管数和新定义的体力比来评估图案。我们的分析表明，图案的变形指数可以表示为单个曲线上的函数，而与混溶性无关。我们提出了通过界面张力测量形成图案的机制，并通过修改的毛细管数和新定义的体力比来评估图案。我们的分析表明，图案的变形指数可以表示为单个曲线上的函数，而与混溶性无关。我们提出了通过界面张力测量形成图案的机制，并通过修改的毛细管数和新定义的体力比来评估图案。我们的分析表明，图案的变形指数可以表示为单个曲线上的函数，而与混溶性无关。