Darcylikningen

Darcylikningen, also known as Darcy's law, is a fundamental principle in fluid dynamics, named after the French engineer Henri Darcy. It describes the flow of a fluid through a porous medium, such as soil or rock. The law states that the volume flow rate or discharge Q of the fluid per unit time is proportional to the negative gradient of the hydraulic head H and the permeability k of the medium, and inversely proportional to the fluid's viscosity μ. Mathematically, this relationship is expressed as:

Q = - (k / μ) * (ΔH / ΔL)

where:

- Q is the volume flow rate,

- k is the permeability of the porous medium,

- μ is the dynamic viscosity of the fluid,

- ΔH is the change in hydraulic head over a distance ΔL.

Darcy's law is widely used in hydrology, petroleum engineering, and soil science to model groundwater flow, oil and gas reservoir behavior, and soil water movement. It assumes that the flow is laminar, the porous medium is homogeneous and isotropic, and the fluid is incompressible. The hydraulic head H is the sum of the elevation head, pressure head, and any other potential energy per unit weight of the fluid. The permeability k is a measure of the medium's ability to transmit fluids and is dependent on the medium's porosity and the size and shape of its pores. The dynamic viscosity μ is a measure of the fluid's resistance to flow.