Diffusion steady-state multidimensional

The newer method of Bortels et al., called multidimensional upwinding method (MDUM) should also be mentioned [127]. It was applied to a problem involving diffusion, convection and migration, both steady state and timemarching. 

When spatial or time multiplexing is employed as a multidimensional separation strategy with a first dimension based on an electrokinetic separation mode, an inherent difficulty arises from the need for the first dimension separation channel to be intersected by one of more second dimension channels. Regardless of whether the first dimension separation is operated in a transient (e.g., CZE) or steady-state (e.g., lEF) mode, electric field lines extending into the intersecting channels result in dispersion of sample out of the first dimension channel, and ultimately to sample loss as diffusion... 

TWINKLE is a multidimensional spatial neutron kinetics code, whieh is patterned after steady-state codes currently used for reactor core design. The code uses an implicit finite-difference method to solve the two-group transient neutron diffusion equations in one, two, and three dimensions. The code uses six delayed neutron groups and contains a detailed multi-region fuel-clad-coolant heat transfer model for calculating point-wise Doppler and moderator feedback effects. The code handles up to 2000 spatial points and performs its own steady-state initialisation. Aside from basic cross-section data and thermal-hydraulic parameters, the code accepts as input basic driving functions, such as inlet temperature, pressure, flow, boron concentration, control rod motion, and others. Various edits are provided (for example, channel-wise power, axial offset, enthalpy, volumetric surge, point-wise power, and fuel temperatures). 

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