26.11 Performing Steady-State Calculations

For steady-state calculations, you will request the start of the solution process using the Run Calculation task page (Figure  26.11.1).

Run Calculation

Figure 26.11.1: The Run Calculation Task Page

Here, you will supply the number of additional iterations to be performed in the Number of Iterations field. (For unsteady calculation inputs, see Section  26.12.1.) If no calculations have been performed yet, ANSYS FLUENT will begin calculations starting at iteration 1, using the initial solution. If you are starting from current solution data, ANSYS FLUENT will begin at the last iteration performed, using the current solution data as its starting point.

By default, ANSYS FLUENT will update the convergence monitors (described in Section  26.13) after each iteration. If you increase the Reporting Interval from the default of 1 you can get reports less frequently. For example, if you set the Reporting Interval to 2, the monitors will print or plot reports at every other iteration. Note that the Reporting Interval also specifies how often ANSYS FLUENT should check if the solution is converged. For example, if your solution converges after 40 iterations, but your Reporting Interval is set to 50, ANSYS FLUENT will continue the calculation for an extra 10 iterations before checking for (and finding) convergence.

When you click the Calculate button, ANSYS FLUENT will begin to calculate. During iteration, a Working dialog box is displayed. Clicking the Cancel button or typing <Control-C> in the ANSYS FLUENT console will interrupt the iteration, as soon as it is safe to stop. (See below for more details.)

Updating UDF Profiles

If you have used a user-defined function (UDF) to define any boundary conditions, properties, etc., you can control the frequency with which the function is updated by modifying the value of the UDF Profile Update Interval. If UDF Profile Update Interval is set to $n$, the function will be updated after every $n$ iterations.

By default, the UDF Profile Update Interval is set to 1. You might want to increase this value if your profile computation is expensive. See the separate UDF Manual for details about creating and using UDFs.

Interrupting Iterations

As mentioned above, you can interrupt the calculation by clicking the Cancel button in the Working dialog box that appears while the solver is calculating. In addition, on most, but not all, computer systems you will be able to interrupt calculations using a control sequence, usually <Control-C>. This allows you to stop the calculation process before proceeding with the remainder of the requested iterations.

Resetting Data

After you have performed some iterations, if you decide to start over again from the first iteration (e.g., after making some changes to the problem setup), you can reinitialize the solution using the Solution Initialization task page, as described in Section  26.9.1.