Simulation and Nonlinear Instability Investigation of Two Miscible Fluid Flow in Homogeneous Porous Media

Fingering phenomena in porous media has a lot of applications and various models in industries and natural issues. Recently several studies have been done on the stability of fluid in porous media. In this paper, the nonlinear instability of viscous fingering in a homogenous porous media is studied. Using a Fourier spectral method as the basic scheme for numerical simulation, equations transferred to Fourier space. The effect of mobility ratio on mixing length, sweep efficiently and transversely average concentration is examined and results indicate that in a high mobility ratio, sweep efficiently decrease and mixing length increase. Also estimation on beginning of viscous fingering instability has been done by analyzing of mixing length›s graph. In this paper, a new finger interaction mechanism is reported for the first time and named trifurcated tip, other mechanisms reported by previous researcher in the case of high mobility ratio, all are observed in this paper. Also the development of the new finger structures is explained by examining the velocity field which is superposed on the concentration contour.