727 passes Mach one

[retired guy]

Not to nitpick, but correction: Coanda at work here, not Bernoulli.

Burnulli`s principal....An increase in speed of a fluid(or gas) over a curved surface results in a decrease in pressure over the same surface.
Coanda`s principal...observed that a stream of energy emerging from a nozzle tends to follow a nearby curved surface.
Sounds like they are both at work here.