Building wake

Huber, A. H., and Snyder, W. H., Building wake effects on short stack effluents, pp. 235-242 in Preprints, Third Symposium on Atmospheric Turbulence, Diffusion and Air Quality. October 19-22, 1976, Raleigh, NC. American Meteorological Society, Boston, 1976. 

The modeling package, delivered to the EPA, includes nationwide data bases for emissions, dispersion meteorology, and population patterns. These data are used as input for a Gaussian plume model for point sources and a box model for urbanwide area sources. Prototype modeling is used for point sources that are too numerous to define individually. Building wake effects and atmospheric chemical decay are addressed. 

Fackrell, 1984 [174]). Hunt and Castro, 1981 [282] extended the work of Vincent, 1977 [636] to dispersion of clouds in building wakes. The basic concepts for plumes were developed by Hunt and Mulhearn, 1973 [280], Puttock and Hunt, 1979 [513], Hunt et al., 1979 [281] and Davidson et al., 1995 [143], Robins and Apsley, 2000 [539] brought many of the results together for dispersion from local sources near cuboid obstacles in the Buildings Module of the ADMS model. Hall et al., [243, 247] extended the results to cover dispersion around many obstacles in their code UDM. We describe the characteristic processes below and outline the simple models that have been developed. 

Hunt, A., and Castro, I.P. (1981) Scalar dispersion in model-building wakes, J. Wind Engineering and Industrial Aerodynamics 17, 89-115. 

Kothari, K.M., Peterka, J.A., and Meroney, R.N. (1986) Perturbation analysis and measurements of building wakes in a stably-stratified turbulent boundary layer, Journal of Wind Engineering and Industrial Aerodynamics, 25,49-74. 

Consistent with Regulatory Guide 1 4, the 0 to 8 hr release dispersion factor includes a Building Wake Correction factor of 2.1 based upon a maximum building cross-sectional area of 748 m. ... 

Aero namic wake flows of all kinds, including stack downwash, building wakes, highway vehiele wakes, and wakes generated by terrain obstacles... 

FIGURE 3J7 Non-GEP stack. Stack allows exhaust gases to be entrained in building wakes and eddy currents. 

Ejfective Height of an Emission The effective height of an emission rarely corresponds to the physical height of the stack. If the plume is caught in the turbulent wake of the stack or of buildings in... 

Huber, A. H., Incorporating building/terrain wake effects on stack effluents, pp. 353-356 in Preprints, Joint Conference on Applications of Air Pollution Meteorology. November 29-December 2, 1977, Salt Lake City, UT. American Meteorological Society, Boston, MA, 1977. 

Vortex Fluid flow that takes place with rotary motion, such as that observed in the wakes of buildings. 

The effective height of an emission rarely corresponds to tlie physical height of tlie source or the stack. If tlie plume is caught in tlie turbulent wake of tlie stack or of buildings in the vicinity of tlie source or stack, tlie effluent will be mixed rapidl) downward toward the ground. If the plume is emitted free of these turbulent zones, a number of emission factors and meteorological factors influence tlie rise of the plume. 

The stack gas e.xit velocity should be greater tluiti 60 ft/s so tliat stack gases will escape the turbulent wake of the stack. In many cases, it is good practice to liave the gas e.xit velocity on the order of 90 or 100 ft/s. 3. A stack located on a building should be located in a position tliat will assure tliat the exliaust escapes tlie wakes of nearby structures. 

In order to prepare for hibernation, the animal must build up its body weight and increase its body fat. This is important, since the animal will be living off its own body fat during the months of hibernation. Of course, once the period of hibernation is over, the animal wakes up to find itself slim and trim once again ... 

Flows within the wake region of buildings are extremely complex and generally applicable equations are difficult to derive. In practice, the estimation of near-field concentrations in complex flows around buildings is best undertaken in a wind tunnel. However this may not be possible in many situations and relatively simple numerical estimates may be required. The following discussion outlines a procedure which is necessarily very approximate but which could be used as an initial screening estimate for concentrations which should be accurate to about a factor of 3. 

A zone of combustion, accompanied by a build-up of the pressure, developed in the wake of the shock front. This led sometimes to a) smooth acceleration of the latter until detonation was established b) formation of shock waves which overtook the front and caused deton or c) decay of the initial shock without deton. Compn and pressure limits were observed beyond which... 

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