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Unstable or Neutral - Crossover Between
Momentum and Buoyancy__

For
cases with stack gas temperature greater than or equal to ambient
temperature, it must be determined whether the plume rise is dominated by
momentum or buoyancy. The crossover temperature difference, (DT)_{c},
is determined as follows:

for
F_{b} < 55,

(DT)_{c}=0.0297 T_{s}(v_{s}/d_{s}^{2})^{1/3}
(9)

and
for F_{b} >= 55,

(DT)_{c}=0.00575 T_{s}(v_{s}^{2}/d_{s})^{1/3}
(10)

If
DT, exceeds or equals (DT)_{c}, plume rise is assumed to be buoyancy
dominated, otherwise plume rise is assumed to be momentum dominated.

__
Unstable or Neutral - Buoyancy Rise__

For
situations where DT exceeds (DT)_{c} as determined above, buoyancy
is assumed to dominate. The distance to final rise, x_{f}, is
assumed to be 3.5x^{*}, where x^{*} is the distance at which
atmospheric turbulence begins to dominate entrainment. The value of x_{f}
is calculated as follows:

for F_{b}
< 55:

x_{f}=49F_{b}^{5/8}
(11)

and for
F_{b} >= 55:

x_{f}=119F_{b}^{2/5}
(12)

The
final effective plume height, h_{e} (m), is determined as

for F_{b}
< 55:

h_{e}=h_{s}+(21.425 F_{b}^{3/4}/u_{s})
(13)

and for
F_{b} = 55:

h_{e}=h_{s}+(38.71 F_{b}^{3/5}/u_{s})
(14)

__
Unstable or Neutral - Momentum Rise__

For
situations where the stack gas temperature is less than or equal to the
ambient air temperature, the assumption is made that the plume rise is
dominated by momentum. If DT is less than (DT)_{c}, the assumption
is also made that the plume rise is dominated by momentum. The plume height
is calculated as:

h_{e}=h_{s}+3d_{s}(v_{s}/u_{s})
(15)

Briggs suggests that this equation is most applicable when v_{s}/u_{s}
is greater than 4.

**
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Algorithms I -
Algorithms
II -
Algorithms III -
Algorithms IV -
Algorithms V -
Algorithms VI -
Algorithms VII -
Algorithms VIII -
Algorithms IX -
Algorithms X

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Air
pollution map (XY-Plane) produced by continuous discharge in time (three
stacks).
The red colour represents
high pollutant
concentrations. Wind: SW (225 degrees).

Pollution map (XY-Plane)
produced by continuous discharge in a
road
region. The
fucshia squares
represent the road line (position of
the
different point sources) in a XY-Plane.
The red colour represents
high pollutant concentrations.

**
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Canarina Algoritmos
Numéricos, S.L.

Environmental software solutions

Canary Islands, Spain

e-mail:
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ISC3 (VOL. 2)

SOLUTIONS: __
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COMMANDS:
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ALGORITHMS:
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II -
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EMISSIONS:
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Pollutants I -
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GRAPHS:
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