The crosssectional area locally occupied by the gas phase of a multiphase flow, relative to the crosssectional area of the conduit at the same local position.
Related Terms 
INTERFACIAL TENSION (IFT)
The energy per unit area present at the boundary of two immiscible liquids. It is usually expressed in dynes/cm (ASTM Designation D 971.)

HIGH
An area of high pressure. Since a high is, on a synoptic chart, always associated with anticyclonic circulation, the term is used interchangeably with ANTICYCLONE

HORN ANTENNA
An antenna consisting of a waveguide the crosssectional area of which increases toward the open end. Often shortened to HORN.

PERMEABILITY
The relationship of flow per unit area to differential pressure across a filter medium.

HOLDUP
The crosssectional area locally occupied by one of the phases of a multiphase flow, relative to the crosssectional area of the conduit at the same local position.

MULTIPHASE FRACTION METER
A device for measuring the phase area fractions of oil, gas and water of a multiphase flow through a crosssection of a conduit.

PHASE AREA FRACTION
The crosssectional area locally occupied by one of the phases of a multiphase flow, relative to the crosssectional area of the conduit at the same local position.

ICE COVER
The ratio, expressed in tenths, of the amount of ice to the total area of sea surface in a defined area; this locale may be global, hemispheric, or a specific geographic entity.

MULTIPHASE METER
A device for measuring the phase area fractions and flow rates of oil, gas and water of a multiphase flow through a crosssection of a conduit. It is necessary to specify whether the multiphase meter measures volume or mass flow rates.

PHASE VELOCITY
The velocity of one phase of a multiphase flow at a crosssection of a conduit. It may also be defined by the relationship (Superficial phase velocity * Phase area fraction).
