There were only two things I ever got out of fluid dynamics that made any sense:
The impact of a jet of fluid on a surface (pissing, as you’d say in the vernacular)
the release of energy in a river (what you’d call rapids, again in the vernacular).
The release of energy in in a river (or open channel hydraulics to bore you to death) was called a (or an) hydraulic jump.
Now, who said reading blogs was a waste of time?