The instability at the interface between two parallel flows of immiscible liquids through a uniform planar pore is studied by using linear stability analysis. A characteristic equation determines the growth rate versus wavenumber, and instability conditions are determined. The instability is governed by a dimensionless group relating the ratio of gravity to interfacial tension. Interfacial tension has a stabilizing effect resisting the destabilizing gravitational force, limiting the range of wavelengths of unstable disturbances to be longer than a minimum critical wavelength. Application to flow of steam condensate and mobilized bitumen in the steam-assisted gravity drainage process shows that the instability is possible only over a specific range of temperatures given the densities of the steam condensate and oil in the reservoir. This instability may contribute to forming an emulsion which could help support oil drainage if the oil is hosted by the more mobile water phase.

中文翻译：

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孔隙中两种不混溶液体平行流动的不稳定性及其在蒸汽辅助重力排水中的应用

采用线性稳定性分析方法研究了通过均匀平面孔的不混溶液体的两个平行流之间界面的不稳定性。特征方程确定了生长速率与波数的关系，并确定了不稳定条件。不稳定性由与重力与界面张力之比相关的无量纲组控制。界面张力具有抵抗不稳定重力的稳定作用，将不稳定扰动的波长范围限制为大于最小临界波长。蒸汽辅助重力排水过程中蒸汽凝析油和流动沥青流动的应用表明，在给定油藏中蒸汽凝析油和油的密度的情况下，只有在特定温度范围内才可能出现不稳定性。