An island of stability in a sea of fingers: emergent global features of the viscous-flow instability

作者：Bischofberger Irmgard^*; Ramachandran Radha; Nagel Sidney R

来源：Soft Matter, 2015, 11(37): 7428-7432.

DOI：10.1039/c5sm00943j

The displacement of a more viscous fluid by a less viscous one in a quasi-two dimensional geometry leads to the formation of complex fingering patterns. This fingering has been characterized by a most unstable wavelength, lambda(c), which depends on the viscosity difference between two immiscible fluids and sets the characteristic width of the fingers. How the finger length grows after the instability occurs is an equally important, but previously overlooked, aspect that characterizes the global features of the patterns. Long after the instability onset, once the fingers are growing in a nearly steady-state regime, there is a stable inner region where the outer fluid is completely displaced.

• 出版日期2015