plumestructure

Plume structure refers to the spatial organization inside a plume—a rising stream of fluid that transports heat, mass, or particulates away from a source. The term is used across disciplines to describe how the plume's core, mixing layer, and ambient interactions shape its evolution. Plumes form in volcanic eruptions and industrial smokestacks, in oceanic hydrothermal vents and freshwater discharges, and in astrophysical jets, where buoyancy and momentum drive ascent.

A typical buoyant plume comprises a dense core with elevated temperature or concentration, a turbulent shear layer where ambient fluid is entrained, and a spreading region where the plume becomes neutrally buoyant and disperses as an umbrella. Entrainment dilutes the plume and controls its rise and spread; the balance among buoyancy, momentum, and ambient stratification determines maximum height, lateral extent, and lifetime.

Modeling and measurement: The Morton-Taylor-Turner framework captures many plumes with integral conservation equations for mass, momentum, and buoyancy, yielding predictions for rise height, radius, and dilution. Turbulent fluxes and stratification introduce complexity, often addressed with computational fluid dynamics (CFD) simulations or remote sensing. Observations employ lidar, radar, satellite radiometry, and in situ samplers.

Applications and significance: Understanding plume structure informs hazard assessment for volcanic ash plumes and industrial emissions, supports air-quality and climate studies, and guides environmental management and safety protocols. The term also appears in laboratory studies of turbulent jets and in astrophysical contexts where relativistic or magnetohydrodynamic effects modify the classic buoyant-plume picture.