(v) The bythagorean triplets
ar md - 1 m2 + 1 and
Answers
Answer:
A darcy (or darcy unit) and millidarcy (md or mD) are units of permeability, named after Henry Darcy. They are not SI units, but they are widely used in petroleum engineering and geology. Like some other measures of permeability, a darcy has dimensional units in length².
Contents
1 Definition
2 Origin
3 Conversions
4 References
Definition
Permeability measures the ability of fluids to flow through rock (or other porous media). The darcy is defined using Darcy's law, which can be written as:
Q = A k Δ P μ Δ x {\displaystyle Q={\frac {Ak\,\Delta P}{\mu \,\Delta x}}} {\displaystyle Q={\frac {Ak\,\Delta P}{\mu \,\Delta x}}}
where:
Q {\displaystyle Q\,} Q\, is the volumetric fluid flow rate through the medium
A {\displaystyle A\,} A\, is the area of the medium
k {\displaystyle k\,} k\, is the permeability of the medium
μ {\displaystyle \mu \,} \mu \, is the dynamic viscosity of the fluid
Δ P {\displaystyle \Delta P\,} \Delta P\, is the applied pressure difference
Δ x {\displaystyle \Delta x\,} \Delta x\, is the thickness of the medium
The darcy is referenced to a mixture of unit systems. A medium with a permeability of 1 darcy permits a flow of 1 cm³/s of a fluid with viscosity 1 cP (1 mPa·s) under a pressure gradient of 1 atm/cm acting across an area of 1 cm².
Typical values of permeability range as high as 100,000 darcys for gravel, to less than 0.01 microdarcy for granite. Sand has a permeability of approximately 1 darcy.
Explanation: