) and select There are two consistent stabilization methods: Streamline diffusion and Crosswind diffusion. Usually, both check boxes for these methods are selected by default and should remain selected for optimal performance. Consistent stabilization methods do not perturb the original transport equation.
In some cases, if the Crosswind diffusion check box is selected, the Lower gradient limit glim (SI unit: K/m) field is available. This variable corresponds to the smallest concentration change across an element considered by the stabilization, and is used to make sure that the crosswind diffusion expressions are valid also in regions with small to negligible concentration changes.
In some cases, and for both consistent stabilization methods, select a Residual (or Equation Residual). Approximate residual is the default setting and it means that derivatives of the diffusion tensor components are neglected. This setting is usually accurate enough and is faster to compute. If required, select Full residual instead.
) and select There is usually just one inconsistent stabilization method — Isotropic diffusion. This method is equivalent to adding a term to the diffusion coefficient in order to dampen the effect of oscillations by making the system somewhat less dominated by convection. If possible, minimize the use of the inconsistent stabilization method because by using it you no longer solve the original problem. By default, the Isotropic diffusion check box is not selected, because this type of stabilization adds artificial diffusion and affects the accuracy of the original problem. However, this option can be used to get a good initial guess for under-resolved problems.
If required, select the Isotropic diffusion check box and enter a Tuning parameter δid as a scalar positive value. The default value is 0.25 (a reasonable value to start with is roughly 0.5 divided by the element order). A higher value adds more isotropic diffusion.
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