Surfactant Variations in Porous Media Localize Capillary Instabilities during Haines Jumps
Surfactant Variations in Porous Media Localize Capillary Instabilities during Haines Jumps
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DOI：
10.1103/physrevlett.120.028005
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发表时间：
2018-01-12
影响因子：
8.6
通讯作者：
Berg, Steffen
中科院分区：
文献类型：
--
作者：
Edery, Yaniv;Weitz, David;Berg, Steffen
我们使用共聚焦显微镜测量了多孔介质中含有表面活性剂的被捕获的润湿相和流动的侵入的非润湿相之间的速度和界面张力。我们将流体-流体界面的界面张力变化与表面活性剂浓度联系起来，并表明这些变化使毛细力的不稳定局部化，并导致非润湿流体的快速局部侵入，从而导致海恩斯跳变。表面活性剂浓度的这些空间变化是由流体-流体界面的速度变化引起的，即使在其他非常均匀的孔隙结构和压力条件下，也会导致海恩斯跳的局部化。我们的结果为海恩斯跳的性质提供了新的见解，海恩斯跳是多孔介质中流动中最普遍和最重要的不稳定性之一。
We use confocal microscopy to measure velocity and interfacial tension between a trapped wetting phase with a surfactant and a flowing, invading nonwetting phase in a porous medium. We relate interfacial tension variations at the fluid-fluid interface to surfactant concentration and show that these variations localize the destabilization of capillary forces and lead to rapid local invasion of the nonwetting fluid, resulting in a Haines jump. These spatial variations in surfactant concentration are caused by velocity variations at the fluid-fluid interfaces and lead to localization of the Haines jumps even in otherwise very uniform pore structure and pressure conditions. Our results provide new insight into the nature of Haines jumps, one of the most ubiquitous and important instabilities in flow in porous media.