Channelling vertical stratification

Thus, in summary, note that poor linear, areal and vertical waterflooding efficiency may occur for unfavourable M, and that the role of polymer is basically to remedy this situation by reducing M. However, for linear and areal (homogeneous) sweep improvement it is necessary only to reduce M to approximately unity. In cases where larger scale heterogeneities occur, e.g. vertical stratification or areal channel sands, it may be necessary to reduce M to a value considerably below unity. The desirable M for such cases will depend on the details of the particular system of interest. This may also be constrained by certain practical problems such as the magnitude of additional pressure build-up that is acceptable when using viscous polymers in the field. 

The model of the recuperator uses the default volume control flags except for the following 1) the vertical stratification model is not used (since not relevant to single phase flow), 2) the ORNL ANS narrow channel model heat transfer correlation Is applied, and 3) wail friction is not computed along the direction of flow. The ORNL ANS model provides the best approximation of experimental data for the low Prandtl number gas being used and the laminar flow regime. The Nusselt number from the ORNL ANS model is adjusted for both compact heat exchanger effects and Reynolds number... 

The tidal fronts near the boimdary of the shallow coastal area and channel are developed dm-ing smnmer when thermal stratification is established in the channel and a vertically homogenous water mass developed by strong tidal currents is sustained in the shallow coastal area. These fronts may affect the transport of terrestrial materials (including N) to offshore locations, and hence the biogeochemical activity. 

Considerations of distributions across the flow channel, transverse to the primary flow direction, were first included in basically one-dimensional models by approximating the temperature distribution in the fluid parallel to the flow direction. Recently there is an increasing application of CFD to various single- and two-phase thermal-hydraulic analyses, including NCLs and supercritical fluid states, in nuclear power systems. These approaches also allow for resolution of the thermal stratification in horizontal and vertical sections of the loop as well as resolution of gradients normal to the primary flow direction and the consequent effects on calculated stability. Fully three-dimensional analyses are becoming the norm, but only for simple idealized single-phase cases. 

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