Influence of double diffusive effects on miscible viscous fingering

Area of Science:

• Fluid dynamics
• Porous media physics
• Chemical engineering

Background:

• Viscous fingering typically occurs when low-viscosity fluids displace high-viscosity fluids in porous media.
• Double diffusive effects arise from differences in diffusion rates of fluid components, influencing overall fluid viscosity.

Purpose of the Study:

• To investigate how double diffusive effects impact miscible viscous fingering.
• To explore the destabilization of classically stable displacement scenarios (high-viscosity displacing low-viscosity).

Main Methods:

• Analysis of instability scenarios in a parameter space defined by log-mobility ratios R(s) and R(f).
• Parametrization using the ratio of diffusion coefficients, δ.
• Numerical simulations of the full nonlinear problem.

Main Results:

• Identified various instability scenarios driven by differential diffusion.
• Confirmed the destabilization of stable displacement configurations.
• Demonstrated the significant influence of differential diffusion on nonlinear fingering dynamics.

Conclusions:

• Double diffusive effects are critical in determining viscous fingering behavior.
• Differential diffusion can lead to unexpected instabilities in porous media flows.
• Numerical simulations validate theoretical predictions of these complex fluid dynamics.