Proper Orthogonal Decomposition with Method of Snapshots implementation. I will soon upload an example file. But the basic procedure is as per the paper by Drualt - https://link.springer.com/article/10.1007%2Fs00348-005-0035-3
The procedure works best when you have velocity files in a folder. That way, the code reads file from the folder and reconstructed velovity field is also written as files.