9.1
Plume rise: a revisit of old problems and some new ones
Jeffrey C. Weil, CIRES/Univ. of Colorado, Boulder, CO
Most industrial pollution sources are stacks with discharges of momentum
and heat, and the resulting plume rise can be considerable (100's of
meters) and can lead to substantial dilution of plume constituents before
they reach the ground. For power plants and other large sources, the
major contribution to the rise is from the heat or buoyancy flux whereas
source momentum can be important for smaller sources typically found
in light manufacturing. Plume rise varies not only with the source
conditions but also with the local meteorological conditions---the wind
speed, ambient stratification, and the ambient turbulence---and is a
strong function of the downstream distance. In this paper, we focus
on an integral model of plume rise (Briggs, 1994; Weil, 1988) in which
one considers the differential equations governing the total fluxes
of mass, momentum, and energy through a cross section. The equations
are closed using an entrainment assumption. This approach has been
successful in predicting the rise and growth of plumes close to the
source and the "leveled off" height in stable air.
Key attention will be given to two unresolved historical plume rise
issues: 1) the penetration of an elevated inversion by a buoyant plume,
and 2) the prediction of the "final rise" due to turbulence in a
neutral or convective boundary layer. A more recent problem is the
rise, growth, and behavior of a buoyant plume in or near the
aerodynamic turbulent wake of a building. These problems are analyzed
using the governing theory or model together with laboratory
experimental data and field observations.
Session 9, Plume Rise: Modeling and Measurements
Wednesday, 20 January 2010, 1:30 PM-2:30 PM, B308
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