Transverse mixing zone

The preceding discussion assumed that a chemical is injected into a river or stream uniformly across a river cross section. In fact, spills and other inputs are rarely introduced uniformly across a channel, and a certain distance must be traveled before a chemical concentration becomes uniform across the channel. For a chemical released at a river bank, the length L of this transverse mixing zone can be roughly estimated by equating the lateral standard deviation (concentration distribution to the width of the river,... 

Nambi IM, Werth CJ, Sanford RA, Valocchi AJ. (2003). Pore-scale analysis of anaerobic growth along the transverse mixing zone of an etched silicon pore network. Environmental... 

EXAMPLE 5.3 River mixing zone for waste discharge (evaluated as a point source with transverse diffusion)... 

The wave is a stable structure which spreads from the introduction point of the main flow into the mixing zone, along the x-coordinates, in the form of a wave without any transversal diffusion (Figure 4.1d). 

While the flow of a fluid through a packed bed at a given velocity, v, is a coimnon situation in practice, the description of the problem is quite complicated even in a one-dimensional space with fluids of uniform properties. This is due to the fact that mixing takes place both longitudinally (in the direction of flow) and transversely (perpendicular to the flow). Suppose at i=0 a dot of traced fluid (such as dye) of concentration c, rather than over the entire face, is injected. This situation is schematically shown in Fig. 3.2. As the dot moves from left (face 1) to right (face 2) with the flow, it will spread in the direction of flow and perpendicular to the flow. At face 2 the dot is transformed into an ellipse with concentration varying across it. There are several methods to obtain partial differential equations describing the concentration behaviour of the mixed zone as a function of time and position, to model the phenomenon shown in Fig. 3.2. 

Figure 3.5 gives a schematic illustration of the key elements of a cw CO chemical laser. Mixing of CS2 with O atoms occurs in a subsonic mixing zone a transverse optical axis is employed. Typical cavity pressures in cw CO lasers range from about 5 to 50 torr. Chemical efficiencies for these lasers can exceed 30% based on the fraction of the energy release of reaction (3.2) which appears as laser power output. ... 

Fig. 15—Comparison between low-speed mixed lubrication and dry contact a ground surface with transverse texture, (a) Profiles of pressure and film thickness along the x direction at y=0. (b) An enlarged view for the marked zone in 15(a). (c) The contour plot of film thickness, (d) 3-D plot of pressure distribution.

Outside of a small region around the center of the Brillouin zone, (the optical region), the retarded interactions are very small. Thus the concept of coulombic exciton may be used, as well the important notions of mixure of molecular states by the crystal field and of Davydov splitting when the unit cell contains many dipoles. On the basis of coulombic excitons, we studied retarded effects in the optical region K 0, introducing the polariton, the mixed exciton-photon quasi-particle, and the transverse dielectric tensor. This allows a quantitative study of the polariton from the properties of the coulombic exciton. 

In order to achieve optimum heat recovery for the kiln system, it is necessary to prevent the air from the after-cooling zone from mixing with the secondary or the tertiary air. For this reason a partition to prevent transverse flow is provided at the end of the recuperative zone, in the hot air part of the cooler. Besides, from this point the roof of the cooler housing slopes upwards to the kiln and also in some systems upwards towards the clinker breaker, so as to obtain constant velocities... 

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