Which statement best describes Darcy's Law as applied to porous media?

Which statement best describes Darcy's Law as applied to porous media?

• A. It relates volumetric flux to pressure gradient
• B. It assumes turbulent flow
• C. It ignores viscosity
• D. It requires multiphase saturation

Answer: (A)

Darcy's Law describes how a fluid moves through a porous medium under a driving pressure gradient. The fluid flux through a cross-section is proportional to the gradient of pressure (or hydraulic head), with the proportionality constant set by the medium's permeability and the fluid's viscosity. The flow goes from high pressure to low pressure. This rests on laminar, viscous-dominated flow at the pore scale; turbulent conditions wouldn’t follow the same linear relationship. Viscosity matters because it resists flow, reducing flux for a given gradient. While the law can be extended to multiple fluids, the simplest, most direct statement is about the single-phase relationship between volumetric flux and pressure gradient.

Darcy's Law describes how a fluid moves through a porous medium under a driving pressure gradient. The fluid flux through a cross-section is proportional to the gradient of pressure (or hydraulic head), with the proportionality constant set by the medium's permeability and the fluid's viscosity. The flow goes from high pressure to low pressure. This rests on laminar, viscous-dominated flow at the pore scale; turbulent conditions wouldn’t follow the same linear relationship. Viscosity matters because it resists flow, reducing flux for a given gradient. While the law can be extended to multiple fluids, the simplest, most direct statement is about the single-phase relationship between volumetric flux and pressure gradient.