Inertia onset in disordered porous media flow

Area of Science:

• Fluid dynamics
• Porous media physics
• Rheology

Background:

• Understanding fluid flow in porous media is crucial for various applications.
• The transition to inertial flow regimes in porous media is not well-defined.
• Channeling effects significantly influence flow paths in disordered porous structures.

Purpose of the Study:

• To investigate the onset of the inertial flow regime at the pore level.
• To analyze qualitative and quantitative changes in flow structure with increasing Reynolds number.
• To identify the critical Reynolds number for the onset of inertia and vortex formation.

Main Methods:

• Simulating fluid flow in 3D disordered porous media across a wide range of Reynolds numbers (0.01–100).
• Analyzing flow structure by examining tortuosity, spatial kinetic energy localization, and negative streamwise velocity.
• Quantitatively assessing the weakening of channeling effects.

Main Results:

• The onset of inertia was detected at a Reynolds number of approximately 0.1, indicated by tortuosity and participation number derivatives.
• This onset is an order of magnitude lower than suggested by friction factor analyses.
• Vortex structures were observed at Reynolds numbers two orders of magnitude higher than the inertia onset.

Conclusions:

• The inertial flow regime in porous media begins around Re ≈ 0.1.
• Traditional methods using friction factors underestimate the onset of inertia.
• Inertia significantly impacts flow behavior, with vortex formation occurring much later in the inertial regime.