**hydraulic diffusivity** — See diffusivity, hydraulic … Lexicon of Cave and Karst Terminology

**diffusivity, soil water** — The hydraulic conductivity divided by the differential water capacity (care being taken to be consistent with units), or the flux of water per unit gradient of moisture content in the absence of other force fields [22] … Lexicon of Cave and Karst Terminology

**Groundwater flow equation** — Used in hydrogeology, the groundwater flow equation is the mathematical relationship which is used to describe the flow of groundwater through an aquifer. The transient flow of groundwater is described by a form of the diffusion equation, similar … Wikipedia

**Disc permeameter** — The disc permeameter is a field instrument used for measuring water infiltration in the soil, which is characterized by in situ saturated and unsaturated soil hydraulic properties. It is mainly used to provide estimates of the hydraulic… … Wikipedia

**Earth Sciences** — ▪ 2009 Introduction Geology and Geochemistry The theme of the 33rd International Geological Congress, which was held in Norway in August 2008, was “Earth System Science: Foundation for Sustainable Development.” It was attended by nearly… … Universalium

**fluid mechanics** — an applied science dealing with the basic principles of gaseous and liquid matter. Cf. fluid dynamics. [1940 45] * * * Study of the effects of forces and energy on liquids and gases. One branch of the field, hydrostatics, deals with fluids at… … Universalium

**Dimensionless quantity** — In dimensional analysis, a dimensionless quantity or quantity of dimension one is a quantity without an associated physical dimension. It is thus a pure number, and as such always has a dimension of 1.[1] Dimensionless quantities are widely used… … Wikipedia

**Graetz number** — In fluid dynamics, the Graetz number (Gz) is a dimensionless number that characterises laminar flow in a conduit. The number is defined as::Gz={d iover L}RePrwhere: di is the internal diameter in round tubes or hydraulic diameter in arbitrary… … Wikipedia

**Supercritical fluid** — A supercritical fluid is any substance at a temperature and pressure above its thermodynamic critical point. It can diffuse through solids like a gas, and dissolve materials like a liquid. Additionally, close to the critical point, small changes… … Wikipedia

**Fick's laws of diffusion** — For the technique of measuring cardiac output, see Fick principle. Molecular diffusion from a microscopic and macroscopic point of view. Initially, there are solute molecules on the left side of a barrier (purple line) and none on the right. The… … Wikipedia