34.1.13 File/Write/Data...

The File/Write/Data... menu item is used to save a ANSYS FLUENT data file (which has a .dat extension) or parallel data file (which has a .pdat extension). See Sections  4.3.2 and 4.4 for details.

When ANSYS FLUENT writes a data file, the .dat extension is added to the file name specified, unless the name already ends with .dat or .pdat. You can compress data files (but not parallel data files) by appending .gz or .Z to the file name. (See Section  4.1.5 for details about file compression.)