Porous media

ability of a liquid to flow in narrow spaces

350px|thumb|Frameworks of LTA-type (left) and FAU-type zeolites (right) Zeolites are a group of several microporous, crystalline aluminosilicate minerals commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, and oxygen, and have the general formula ･y where is either a metal ion or H+.

Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure the "accessible void", the total amount of void space accessible from the surface (cf. closed-cell foam).

measure of the ability of a porous material to allow fluids to pass through it

total surface of a solid per mass

material containing pores

material with pores between 2 and 50 nm

volume occupied by liquid and gas phases in a soil

Porosimetry is an analytical technique used to determine various quantifiable aspects of a material's porous structure, such as pore diameter, total pore volume, surface area, and bulk and absolute densities.

relation used in the field of fluid dynamics to calculate the pressure drop of a fluid flowing through a packed bed of solids

thumb|A tortuous river (meander of [[Nowitna River, Alaska)]] Tortuosity is widely used as a critical parameter to predict transport properties of porous media, such as rocks and soils. But unlike other standard microstructural properties, the concept of tortuosity is vague with multiple definitions and various evaluation methods introduced in different contexts. Hydraulic, electrical, diffusional, and thermal tortuosities are defined to describe different transport processes in porous media, while geometrical tortuosity is introduced to characterize the morphological property of porous micros

nondimensional number showing the ratio of inertial force to viscous force

Equation describing the penetration length of a liquid into a capillary tube with time

organic or inorganic framework supporting a regular, porous structure

In soil, macropores are defined as cavities that are larger than 75 μm. Functionally, pores of this size host preferential soil solution flow and rapid transport of solutes and colloids. Macropores increase the hydraulic conductivity of soil, allowing water to infiltrate and drain quickly, and shallow groundwater to move relatively rapidly via lateral flow. In soil, macropores are created by plant roots, soil cracks, soil fauna, and by aggregation of soil particles into peds. Macropores can also be found in soil between larger individual mineral particles such as sand or gravel.

material with pores less than 2 nm wide