Page 38 - Understanding Flight

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How Airplanes Fly 25

Fig. 2.7. A jet flying over fog demonstrates downwash. (Photographer Paul Bowen;
photo courtesy of Cessna Aircraft Co.)

the fog, not through it. The hole caused by the descending downwash
is clearly visible.
It should be noted that the speed of the uniform flow over the top of
the wing is faster than the free-stream velocity, which is the velocity of the
undisturbed air a great distance from the wing. The bending of the air
causes the reduction in pressure above the wing. This reduction in
pressure causes acceleration of the air via the Bernoulli effect. Below the