HOMOGENIZATION_MODEL

This command enables or disables the use of the homogenization model and its default settings. The homogenization model is used for multiphase simulations assuming that local equilibrium holds at each node point. When entering phases into a region one of them is entered as MATRIX phase and all other phases as SPHEROID, but it does not matter which one is entered as matrix phase and it does not affect simulations. Homogenization model simulations differs from all other DICTRA module simulations in that it is implemented using an implicit finite volume method in order to increase numerical stability (degree of implicity can be chosen using the SET_SIMULATION_CONDITION command). Because of this, and other factors, homogenization model simulations generally run slower than other comparable simulations.

The Diffusion Module (DICTRA) in Graphical Mode uses a Diffusion Calculator instead of the Console Mode commands. Most of the Console Mode functionality is available on the Diffusion Calculator. However, you cannot use both Graphical Mode and Console Mode in the same simulation.

Syntax	homogenization_model
Prompts	Enable homogenization model: Enter `Y` to enable the homogenization model. If it is already enabled, you can enter `N` to disable it.
	Use default settings /Y/: Press <Enter> to keep the default settings for the homogenization model. Otherwise enter N and follow the prompts.
	Add ideal flux contribution /N/: If you enter `Y` you are prompted as follows: Fractional ideal contribution(0->1) /.01/: Enter a number between zero and one. In multiphase regions the system loses degrees of freedom which may cause fluctuations in the composition profiles. This can be amended by adding a small ideal contribution to the fluxes. The ideal flux contribution should normally not be used.
	Use interpolation scheme /Y/: By default the interpolation scheme is used and it normally speeds up simulations. You are then prompted with the following: Enter number of steps between XMin and XMax /10000/: Enter the number of steps in composition space. In the limit where an infinite number of steps are used, exactly the same solution is obtained as without the interpolation scheme. However, excellent results can be obtained with a reasonable discretization. Linear or logarithmic discretization /Log/: The discretization can be either linear or logarithmic (the default). For the linear discretization the scheme is not used at node points where the content of one or more solutes fall below a certain critical value. For such cases, where a good discretization is required for very low solute contents, the logarithmic discretization can be tried. Fraction of free physical memory to be used /.1/: Enter the fraction of free physical memory to be used by the interpolation scheme. If a value larger than one (1) is entered it is interpreted as the number of MB to be used for the interpolation scheme.
	Use global minimization /N/: By default global minimization is not used in equilibrium calculations. In general, using global minimization significantly increases the simulation time, but there is also a significantly reduced risk for non-converged equilibrium calculations.
	Refresh Jacobian every iteration /N/: If there are convergence problems, enter Y to see if this solves the issue. This does increase computational demand for each iteration.
	Default grid parameter values /Y/: These settings only affect simulations where the grid changes during the simulation. If you enter N, you are prompted with the following.
	Geometrical coefficient (0+ -> 1) /.98/: The geometrical coefficient used in each region.
	Fixed interface width (<0 DISABLES) /-1/: A value larger than zero makes interface widths fixed to that value.
	Grid fineness away from interface /1/: A value other than one causes the grid away from the interface to be coarser (>1) or finer (<1) than what would be obtained just by the geometrical coefficient.
	Interface width fraction (0+ -> 0.1) /.005/: If the interface width is not fixed the program aims for a width equal to this factor times the cell width.
	Consecutive critical time-steps (DT) to delete region /20/: If the width of a region falls below a certain critical value and shrinks monotonically for this number of time-steps it is deleted.