The main use of the CFX-Interpolator is in providing initial conditions from existing results file for use in a new run. However, you can also use the CFX-Interpolator to compare two results files. When used in this mode, you provide it with a two results files, and the CFX-Interpolator writes a new set of variables into one of the results files of the form Pressure.Difference, which is the difference between the pressures in the two results files. These difference variables can then be viewed in CFD-Post. For a description of the general variable syntax, see Quantitative CEL Functions in Ansys CFX in the CFX Reference Guide.

For Release 12.0 and later, this use of the CFX-Interpolator is largely superseded by the ability of CFD-Post to calculate difference variables and to compare two results files in a more flexible way. For details, see Case Comparison in the CFD-Post User's Guide.

The functionality to calculate difference variables using the CFX-Interpolator is available either through Tools > Interpolate Results in the CFX-Solver Manager, or through the cfx5interp command on the command line. See Using the Command Line to Interpolate Results in the CFX-Solver Manager User's Guide for details. See Calculating Difference Variables in the CFD-Post User's Guide for details on how the difference of vector variables such as Velocity is calculated.

For moving mesh cases, the difference variables are calculated using the final mesh positions.