Plume Interaction

When a heat source is located dose to a w ali, the plume may attach to the wall see Fig. 7.69. In this case the entrainment will be reduced compared to the entrainment in a free plume, and the attached plume can be regarded as half the plume from the source, with its mirror image on the other side of the wail see Fig. 7.70. 

The airflow rate from a heat source can then be calculated as half of the flow from a source with a heat emission of 

If the heat source is located in a corner, die airflow rate is equal to 25% of the airflow from a hear source with a heat emission of 

530 CHAPTER 7 principles OF AIR AND CONTAMINANT MOVEMENT INSIDE AND AROUND BUILDINGS 

When several heat sources are located close to each other, the plumes may merge into a single plume see Fig. 7.72. In this case, the source should he regarded as one single source, with the heat emission equal to the sum ot the heat eiiiissiot) from each of the stturccs  

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From a jet-noise perspective, the experience base with the aircraft is invaluable in making the scale-up from laboratory to aircraft (since realistic internal mixing details need to be addressed), and the availability of a complete aircraft capability is also felt to be important since installation effects and plume/plume interactions can have a first-order effect on jet noise [11]. 

A liquefied gas is widely sprayed from the exit developing a multi-phase mixture. In the opening, a narrow, so-called flashing zone is formed in which a certain firaction of the liquid depending on its thermodynamic conditions is spontaneously (flash-) vaporized. Adjacent zones are the zone of flow establishment characterized by a dilution of the jet stream from its boundaries and the zone of established flow with the full development of the plume interacting with the ambient [84]. 

For fast ions, n should have a high value (>4), and similar effects should obtain for plume components affected by laser-plume interaction. Other intriguing observations, such as are shown in Figure 9, have also been made. The clear separation of slow and fast components is strongly indicative of multiple plume processes, separated either in space or time, or both. The complex angle dependencies shown for the fast neutral and charged species are attributed to laser-plume interactions, which are more significant for ions and can lead to... 

Nitrogen Oxides. From the combustion of fuels containing only C, H, and O, the usual ak pollutants or emissions of interest are carbon monoxide, unbumed hydrocarbons, and oxides of nitrogen (NO ). The interaction of the last two in the atmosphere produces photochemical smog. NO, the sum of NO and NO2, is formed almost entkely as NO in the products of flames typically 5 or 10% of it is subsequently converted to NO2 at low temperatures. Occasionally, conditions in a combustion system may lead to a much larger fraction of NO2 and the undeskable visibiUty thereof, ie, a very large exhaust plume. 

The principal shortcoming with SCREENS is the lack of graphical displays. Interactive graphics that enable plume tracking are invaluable in assessing potential environmental impacts and public health risks from episodic releases. There are a... 

The earliest and still widely used dispersion model to compute pollutant concentration profiles is the Gaussian plume model for single or multiple source pollution problems. Box-type model techniques, which can take into account nonlinear interactions among different species arising from chemical reactions, have been used in longer-range dispersion computations. 

Plume height is based on the assumed F stability and 2.5 m/s wind speed, and the dispersion parameter (o, ) incorporates the effects of buoyancy induced dispersion. If x , is less than 200 m, then no shoreline fumigation calculation is made, since the plume may still be influenced by transitional rise and its interaction with the TIBL is more difficult to model. 

Meteorology plays an important role in determining the height to which pollutants rise and disperse. Wind speed, wind shear and turbulent eddy currents influence the interaction between the plume and surroimding atmosphere. Ambient temperatures affect the buoyancy of a plume. However, in order to make equations of a mathematical model solvable, the plume rise is assumed to be only a function of the emission conditions of release, and many other effects are considered insignificant. 

The p coefficient value depends upon the supply air method (e.g., p = 0 with displacement and natural ventilation, P = 1 with convective plume dissipating within the occupied zone due to interaction with supply jets, airflows created by moving objects, etc.). 

The flow rate of the plume through the zone boundary depends on the plume strength and vertical temperature gradient. In the case of a zoning strategy, the plume flow rate may also depend on the air distribution method and device because of the interaction between the plume and the supply air.-... 

Interaction of different flow elements such as jets, plumes, and boundary layers is inherently considered. 

Groundwater contaminant plumes from accidental gasoline releases often contain methyl-tert-butyl ether. Experiments with certain soil microorganisms showed that a culture able to degrade methyl-tert-butyl ether did not degrade benzene and toluene. Further interactions were observed [468]. 

Ribe NM (1988) Dynamical geochemistry of the Hawaiian plume. Earth Planet Sci Lett 88 37-46 Ribe NM G996) The dynamics of plume-ridge interaction 2. Off-ridge plumes. J Geophys Res 101 16195-16204... 

Schilling JG (1991) Fluxes and excess temperatures of mantle plumes inferred from their interaction with migrating mid-ocean ridges. Nature 352 397-403... 

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