[Mounarah]

hello,
In fluent,I don't understand the difference between doing autosave every x timesteps .cas and .dat file by choosing data file quantities /and the automatic export calculations every x timesteps in calculation activities. thanks

[LuckyTran]

Autosave every whatever will save a .dat file every whatever (and sometimes also a .cas file). The .cas and .dat contain everything, the entire mesh and all the variables at all cells. It's also in a .cas and .dat format. Note that in newer versions of Fluent, this also defaults to the new storage format .cas.h5 and .dat.h5 instead. But we call them case and data files still.

Automatic export allows you to write also your results but at surfaces and/or volumes (zones) that you specify. You can specify a few zones or a lot of zones and a few surfaces or a lot of surfaces. It also allows you to write the results in specific formats (specifically, something other than a .dat format). If you wanted to write a .csv table for example, you would do it here. You also choose specific variables to output. You can write only pressure or only temperature and so on.

Using automatic export, you can choose everything everywhere (all variables and all regions) and it ends up being quite similar to writing a .dat file every x timesteps in the sense that you get "results" every x timesteps, but it's still not a .dat file. It could be a pointwise file, a tecplot file, etc.

[Mounarah]

Thank you Lucky. So they lead to same thing but just the formats are different and export calculations is more specific. I can choose one of them and it is working depending on what i want to get.