Ansys Employee

Fluent uses .cas (contains the mesh & all model settings) and .dat (contains the solution data, this needs a .cas file to be usable).  The .cdat is a cut down data file used in CFD Post which also needs a .cas file to work.  CFD stores the instantaneous data, so if you saved data at 0.35s you'll need the .dat or .cdat files for that timestep. 

If you want averaged data either use the time statistics (data sampling in the Solve panel), these need to be turned on before you start iterating. If you want variable v time plots you can use a Report monitor to save these as plots and/or text files for off line processing.