33.14.1 Residual Monitors Dialog Box

You can use the Residual Monitors dialog box to control the residual information that ANSYS FLUENT reports. See Section  26.13.1 for details about the items below.

Controls

Options   selects any combination of the following methods for reporting residuals. See Section  26.13.1 for details.

Print to Console   specifies whether or not to print residuals in the text window after each iteration.

Plot   specifies whether or not to plot residuals in the graphics window (with the window ID set in Window) after each iteration. See Section  26.13.1 for details.

Window   sets the window ID in which the plot will be drawn. When ANSYS FLUENT is iterating, the active graphics window is temporarily set to this window to update the residual plot, and then returned to its previous value. Thus, the residual plot can be maintained in a separate window that does not interfere with other graphical postprocessing.

Iterations to Plot   is the number of history points to display on the residual plot.

Axes...   opens the Axes dialog box, which allows you to modify the attributes of the axes.

Curves...   opens the Curves dialog box, which allows you to modify the attributes of the residual curves.

Iteration to Store   sets the number of residual history points to be stored in the data file. Due to the compaction algorithm used, saving 1000 points does not result in just the last 1000 iterations being saved; the history reaches back quite a bit further than that, but does not save a point at every iteration. Further back in the iteration history, the spacing between saved iterations grows larger. See Section  26.13.1 for details.

Residual Values   controls the normalization and scaling of residuals. See Section  26.13.1 for details.

Normalize   specifies whether or not to normalize the printed or plotted residual for each variable by the value indicated as the Normalization Factor for that variable. The default Normalization Factor is the maximum residual value after the first 5 iterations.

This option is off by default.

Iterations   sets the number of iterations for which ANSYS FLUENT will search for the largest residual to normalize by. (If the Normalize option is turned off, this item will not be editable.)

Scale   specifies whether or not to print or plot scaled residuals for each variable. This option is on by default.

Convergence Criterion   consists of four options that are available for checking an equation for convergence.

absolute   is the default and is available for steady-state cases. The residual (scaled and/or normalized) of an equation at an iteration is compared with a user-specified value. If the residual is less than the user-specified value, that equation is deemed to have converged for a timestep.

relative   is where the residual of an equation at an iteration of a timestep is compared with the residual at the start of the timestep. If the ratio of the two residuals is less than a user-specified value, that equation is deemed to have converged for a timestep.

relative or absolute   is where either the absolute convergence criterion or the relative convergence criterion is met. At that point, the equation is considered converged.

none   is used to disable convergence checking.

Residual   indicates the name of each variable for which residual information is available.

Monitor   indicates whether or not the residuals for each variable are to be monitored. You can toggle monitoring on and off for each variable by turning the corresponding check box in the Monitor list on or off.

Normalization Factor   shows the normalization factor for each variable. The default is the maximum residual value after the first 5 iterations. To set this value manually, enter a new value in the corresponding Normalization Factor field. This list will not appear if the Normalize option is turned off.

Check Convergence   indicates whether or not the convergence of each variable is to be monitored. If convergence is being monitored, the solution will stop automatically when each variable meets its specified convergence criterion. You can check convergence only for variables for which you are monitoring residuals. You can toggle convergence checking on and off for each variable by turning the corresponding check box in the Check Convergence list on or off.

Absolute Criteria   , Relative Criteria shows the residual value for which the solution of each variable will be considered converged. To set this value manually, enter a new value in the corresponding Absolute Criteria/ Relative Criteria field.

Plot   displays the current residual history plot.

Renormalize   sets the normalization factors to the maximum values in the residual histories. Renormalize should be used to renormalize the residual plot in cases where the maximum residuals occur sometime after the first five iterations.