how does the water behind a jet kick up when the plane flies just above it but never touches it?

Answer 1

It's similar to the Venturi Principle, where the jet creates a vacuum effect as it punches a "hole" through the air above the water. Since nature proverbially abhors a vacuum, the surrounding air and the water beneath the hole rush to fill it.

You can create a similar effect by directing the stream from a compressed air blower between two parallel pieces of streamer material. You would think that the pieces of crepe paper would split away from one another; actually, they tend to come together.

Answer 2

Air under compression behaves very like a liquid. The passage of a large body, or a body moving at high speed, creates compression waves that fan out to either side, above, and below the body in motion. The water beneath a low-flying aircraft is disturbed by this compression wave and "splashed" upwards before being drawn into the turbulence wake of the plane.
BTW, a perfectly aerodynamic design would NOT create this kind of compression wave.

Answer 3

The force of the jet propulsion coming from the engine moves outward in a conical shape displacing that which is in its way. Anyone who works at an airport is taught this principle in an effort to avoid injuries. The same force can lift a person and thrown them several feet.

Answer 4

the fact that high speed air molecules flowing from the jet are responsible for the wake in the water.

Answer 5

the wing pushes the air downwards and the water in reaction according to newton's 3rd law of motion comes up after the force is removed with equal magnitude.

Answer 6

Conical, or oblique, shock waves, are angled rearwards, like the bow wave on a ship or boat.

Note: Comments made regarding 3 dimensional conical shock waves, generally apply to 2D oblique shock waves

Answer 7

You watch too many movies.

Answer 8

the same way the wind does!

Answer 9

motion/speed