The first run of POD_BASIS simply takes the TCELL_FLOW data and seeks 16 POD vectors.
Note, from the output file, the singular values associated with each POD vector, which indicate its relative importance:
The main output of the run is the POD vectors, each in a separate file, which can be regarded as flow solutions:
Each of the POD vectors can be plotted by VECTOR_PLOT, using the xy.txt file from the CAVITY_FLOW database. I only plotted the first four:
You can go up to the POD_BASIS_FLOW page.