Species

In the Species tab allows to specify the numerical options for calculating the transport of a chemical species in a fluid.

Numerical parameters dialog, Species tab 

Figure 43. Numerical parameters dialog, Species tab

Item

Description

Parameters

Specifies the parameters for solving the conservation equation for species transport

  • Underrelaxation factor

    At each iteration, when a new value is computed, only this fraction from the variation is taken. Real number between 0 and 1, default is 0.5.

  • Maximal outer iterations

    Number of maximal allowed recomputations of the coefficients of the system of equations for non-linear problems. This reconstruction of the matrix together with the solving is called an “outer iteration”. Integer number, default is 1000.

  • Desired residuum

    Desired accuracy of the computation; must be a small real number, default is 1e-12.

Reference concentration

Gives the reference concentration for the Boussinesq approximation for solutal driven convection. (Default: 0)

Discretization schema

Allows to switch between upwind and central difference discretization for the species transport (default: central).

  • upwinding: Use the upwind discretization. The solution can be combined with the solution of the central discretization scheme using the deffered correction parameter.

  • central schema: Use the central difference schema.

  • Deferred correction: If the upwind discretization is used the user can specify a weight factor between the solution of the upwind and the central schema. Setting the parameter to 0 means full upwinding, while 1 is equivalent to switch to the central schema (default: 0).

Related Procedures

Setting parameters for species transport simulation.

Specifying settings and parameters for computing concentration