4.3.4 Automatic Saving of Case and Data Files

You can request FLUENT to automatically save case and data files at specified intervals during a calculation. This is especially useful for time-dependent calculations, since it allows you to save the results at different time steps without stopping the calculation and performing the save manually.

You can also use the auto-save feature for steady-state problems, to examine the solution at different stages in the iteration history. Automatic saving is specified using the Autosave Case/Data panel (Figure  4.3.1).

File $\rightarrow$ Write $\rightarrow$ Autosave...

Figure 4.3.1: The Autosave Case/Data Panel

You must set the frequency of saves for case and/or data files, and the root filename. Enter the case-saving frequency in the Autosave Case File Frequency field, and the data-saving frequency in the Autosave Data File Frequency field. Both values are set to zero by default, indicating that no automatic saving is performed.

For steady flows you specify the frequency in iterations, and for unsteady flows you specify it in time steps (unless you are using the explicit time stepping formulation, in which case you specify the frequency in iterations). If you define an Autosave Case File Frequency of 10, for example, a case file is saved every 10 iterations or time steps.

If you have limited disc space, restrict the number of files saved by FLUENT using the Overwrite Existing Files option. Enable the Overwrite Existing Files option and set the value of the Maximum Number of Each File Type field. The case and data files are treated separately. For example, if the value of Maximum Number of Each File Type is set to five, FLUENT saves maximum of five case and five data files, irrespective of the frequency. After saving the specified number of files, FLUENT overwrites the earliest existing file.

Enter the filename for the autosave files in the Filename field. The iteration or time-step number and an appropriate suffix ( .cas or .dat) is added to the specified root name. If the specified Filename ends in .gz or .Z, appropriate file compression is performed. See Section  4.1.5 for details about file compression.

All of the autosave inputs are stored in the case file.