33.13 Solution Controls Task Page

The Solution Controls task page allows you to set common solution parameters.

Controls

Courant Number   sets the fine-grid Courant number (time step factor) when the density-based solver is used. See Section  26.4.1 for guidelines on setting the Courant number.

When the pressure-based solver is used for time-independent flows, and the Coupled pressure-velocity scheme is used, the Courant Number is used to stabilize the convergence behavior. See this section in the separate Theory Guide for a correlation of the under-relaxation factor and courant number.

Explicit Relaxation Factors   for the Coupled scheme defines the explicit relaxation of variables between sub-iterations for momentum and pressure. See this section in the separate Theory Guide for information.

Multigrid Levels   specifies the maximum number of coarse levels to be created by the FAS multigrid solver. This item is the same as the Max Coarse Levels under FAS Multigrid Controls in the Multigrid tab of the Advanced Solution Controls dialog box, and it appears only when the density-based explicit solver is used.

Residual Smoothing   contains parameters that govern the use of implicit residual smoothing. (See this section in the separate Theory Guide and Section  26.4.4 for details.) This section of the task page will appear only when the density-based explicit solver is used.

Iterations   sets the number of iterations of the Jacobi smoother to use. If Iterations is 0, then no implicit residual smoothing is performed.

Smoothing Factor   sets the implicit residual smoothing factor. This item will not appear unless Iterations is set to a non-zero value.

Under-Relaxation Factors   contains the under-relaxation factors for all equations that are being solved with the pressure-based solver. (See Section  26.3.2 for details.) In the field next to each equation, you can set the under-relaxation factor for that equation.

When one of the density-based solvers is used, Under-Relaxation Factors will appear only for the following variables, when they are included in your model: solid (for conjugate heat transfer models), turbulence variables, and viscosity. The density-based solvers use a segregated method to solve these equations; all the other equations are solved in a coupled manner, so there are no under-relaxation factors for them.

When Non-iterative Time Advancement is selected for the pressures-based solver, the Non-Iterative Solver Relaxation Factors define the explicit relaxation ( this section in the separate Theory Guide) of variables between sub-iterations and are used to prevent the solution from diverging.

Default   sets the fields to their default values, as assigned by ANSYS FLUENT.

Equations...   displays the Equations dialog box.

Limits...   displays the Solution Limits dialog box.

Advanced...   displays the Advanced Solution Controls dialog box.