Context from the homepage (https://flow5.tech):
An analysis tool for planes and sails operating at low Reynolds numbers
flow5 is a potential flow solver with built-in pre- and post processing functionalities. Its purpose is to make preliminary designs of wings, planes, hydrofoils and sails reliable, fast and user-friendly.
With so many things being called Flow these days, this one is probably the most fitting.
Source code: https://github.com/techwinder/flow5