Of a light, a unique characteristic which can be recognized as imparting a special cautionary significance e.g., a quick flashing characteristic phase indicating a sharp turn in a channel.
Related Terms 
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 FLOW RATE
The amount of one phase of a multiphase flow flowing through the crosssection of a conduit in unit time. The phase flow rate may be specified as phase volume flow rate or as phase mass flow rate.

SLIP VELOCITY
The phase velocity difference between two phases.

SLIP RATIO
The ratio between two phase velocities.

MULTIPHASE FLOW
Two or more phases flowing simultaneously in a conduit; this document deals in particular with multiphase flows of oil, gas and water.

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).

SUPERFICIAL PHASE VELOCITY
The flow velocity of one phase of a multiphase flow, assuming that the phase occupies the whole conduit by itself. It may also be defined by the relationship (Phase volume flow rate / Pipe crosssection).

MIXTURE PHASE
In this document, “phase” is used in the sense of one constituent in a mixture of several. In particular, the term refers to either oil, gas or water in a mixture of any number of the three.

PHASE VOLUME FRACTION
The phase volume flow rate of one of the phases of a multiphase flow, relative to the multiphase volume flow rate.
