Recalling the not completely satisfactory status of the thread dealing
with the depression in venturis, I offer as my Christmas gift to the
list, a technical discussion accompanying a newish software package
offering a computer fluid dynamics visualization of moving bodies.
Clicking the URL shows a boiler-plate on XFlow. Looking to the bottom
right of that page opens a pdf which discusses the particulate approach
to aerodynamics (so beloved of physicists), in particular the aero
modeling clockwork underlying such codes.