快猫短视频

THE swirling turbulence caused by jets taking off and landing
can be a danger for planes in their wake
(see 鈥淏ack to school鈥�).
But a couple of rollers fixed to each wing could solve the problem.

When an aeroplane flies through the air at high speed, a region of low
pressure forms directly behind the plane. Air from above and below the wing gets
sucked in to fill the space, creating a disruptive swirling vortex.

Guo Wei and his colleague Prasad Patnaik at the National University of
Singapore have come up with a simple fix involving two horizontal rollers
parallel to each other. In a 2D simulation of air flowing across a square block,
wake vortices formed as normal. But when two rollers along the back edge of the
block rotated towards each other, they drew air into the space behind the block
and the swirls straightened out, disappearing completely when the rollers
rotated 50 per cent faster than the air flow.

The researchers suggest you could install the rollers along the trailing edge
of aeroplane wings to stop the wake at its source, without increasing drag. But
first they need to show that the trick would work in three dimensions.