a nemati - Iran University of Science & Technology,
b zare - Iran University of Science & Technology,
h saffari - Iran University of Science & Technology,
s.m Hosseinalipoor - Iran University of Science & Technology,

Viscous fingering is an instability which occurs at the interface between two fluids when a fluid of the lower viscosity is injected into a porous media containing a fluid of higher viscosity. An experimental model which consist of two transparent glasses that fluid is injected among them, is introduced to investigate viscous fingering instability. The engraved lower plate made a porous media of specified characteristics that simulates the instabilities more accurately than other conventional approaches such as Hele-Shaw cell. The instabilities was observed and the way that fingers were formed or merged were investigated. Effect of viscosity contrast of the two fluids and the rate of injection were examined and image processing techniques were performed to measure breakthrough time and average position of the injected fluid. It was revealed that by increasing the viscosity contrast or injection rate more fingers were produced and instabilities increase.

Viscous fingering instability, porous media, miscible flow displacement, viscosity contrast, breakthrough time