16 / 2025-11-16 16:08:35

Three-Dimensional Visualization of Gravity-Viscous Displacement Instabilities in Granular Packs（颗粒堆积体中重力-粘滞力不稳定驱替的三维可视化实验）

granular packs,two-phase displacement,three-dimensional experiment,instabilities

Two-phase flow driven by coupled gravitational and viscous instabilities is widely encountered in natural systems and engineering applications. The interfacial dynamics involved in such processes are highly complex and remain insufficiently explored experimentally. In this study, a three-dimensional visualization platform was developed based on Planar Laser-Induced Fluorescence (PLIF) technology to investigate the effects of injection rate and pore structure on immiscible displacement behavior under coupled gravitational-viscous instability conditions. The experimental results reveal significant variations in displacement patterns under different conditions, with four typical morphologies observed: discrete buoyant droplet, slug, fingering, and dendritic fingering cluster. The evolution of these patterns is governed by the coupled interplay among capillary forces, viscous forces, and gravity. This study elucidates the evolution pathways and dominant mechanisms of typical displacement modes, providing both experimental evidence and theoretical insights into multiphase flow instabilities in three-dimensional porous media.