论文标题
使用台式光学扫描仪研究的3D两相流中的竞争重力和粘性效果
Competing gravitational and viscous efects in 3D two-phase flow investigated with a table-top optical scanner
论文作者
论文摘要
我们提出了描述从粘度稳定的流动到重力不稳定的指法的实验和理论，以在3D合成多孔培养基中进行两相流动。通过基于光学索引匹配和激光诱导的荧光，使用我们新开发的台式3D-SCANNER，可以通过详细描述观察。在实验中，从流动池顶部的点源以固定流量率注入的更密集，更粘性的流体置换了粘性较低，密度较小的流体。我们观察到入口附近的一个稳定的入侵区，随着流速的增加，该区域的大小增加，并且最初呈现接近半球形形状。在以后的时间，入侵前线转变为不稳定的模式和指法流程。过渡发生在预测的临界半径RC上，对应于合并后的粘性和重力压力梯度的零。
We present experiments and theory describing the transition from viscosity-stabilized flow to gravitationally unstable fingering for two-phase flow in a 3D synthetic porous medium. Observation is made possible by the use of our newly developed table-top 3D-scanner based on optical index matching and laser-induced fluorescence, which is described in detail. In the experiment, a more dense, more viscous fluid injected at a fixed flow-rate from a point source at the top of the flow cell displaces a less viscous, less dense fluid. We observe a stable invasion zone near the inlet, which increases in size with increasing flow rates, and presents initially a close to hemispherical shape. At later times, the invasion front transits to an unstable mode and a fingering flow regime. The transition occurs at a predicted critical radius, Rc, corresponding to the zero of the combined viscous and gravitational pressure gradient.
