TURBULENCE

[noun]

1. the quality or state of being turbulent; violent disorder or commotion.

2. Hydraulics: the haphazard secondary motion caused by eddies within a moving fluid.

3. Meteorology: irregular motion of the atmosphere, as that indicated by gusts and lulls in the wind.

Etymology: from Latin turbulentus, from turba, “confusion”.

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Turbulence is one of the great unsolved mysteries of classical mechanics. Many physicists and engineers have spent their careers trying to further our understanding of the subject and find the mathematical pattern that underlies its complex motions. But understanding turbulence and representing it artistically may be two different things. This video discusses some neat research that found that some of Vincent van Gogh’s paintings, like “The Starry Night”, display mathematical patterns like those of turbulence. (Video credit: TED Ed)

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Saturday morning Japan’s Mount Ontake erupted unexpectedly, sending a pyroclastic flow streaming down the mountain. Many, though sadly not all, of the volcano’s hikers and visitors survived the eruption. Pyroclastic flows are fast-moving turbulent and often super-heated clouds filled with ash and poisonous gases. They can reach speeds of 700 kph and temperatures of 1000 degrees C. The usual gases released in a pyroclastic flow are denser than air, causing the cloud to remain near the ground. This is problematic for those trying to escape because the poisonous gases can fill the same low-lying areas in which survivors shelter. Heavy ashfall from the flow can destroy buildings or cause mudslides, and the fine volcanic glass particles in the ash are dangerous to inhale. The sheer power and scale of these geophysical flows is stunning to behold. Those who have witnessed it firsthand and survived are incredibly fortunate. For more on the science and history of Mount Ontake, see this detailed write-up at io9. (Image credits: A. Shimbun, source video; K. Terutoshi, source video; via io9)

There’ll be turbulence. You’ll drop
your book to hold your
water bottle steady. Your
mind, mind has mountains, cliffs of fall
may who ne’er hung there let him
watch the movie. The plane’s
supposed to shudder, shoulder on
like this. It’s built to do that. You’re
designed to tremble too. Else break
Higher you climb, trouble in mind
lungs labor, heights hurl vistas
Oxygen hangs ready
overhead. In the event put on
the child’s mask first. Breathe normally
—  Adrienne Rich, from Turbulence

Mystery Solved? How Birds Weather Turbulence

When a bird hits turbulence while flying, it can’t turn on the “fasten seatbelt” sign. Instead, new research shows that it tucks its wings to stabilize its flight.

Scientists were studying the flight of a captive Eurasian steppe eagle (Aquila nipalensis) when they noticed a curious behavior. While soaring, the bird would often briefly fold its wings before resuming its normal flight.

Called wing tucks, these behaviors are not new to scientists: In fact, one of the Wright brothers, Wilbur, coined the term while spending many hours watching bird flight to improve aircraft design in 1908.

But the scientists began to wonder if the eagle’s frequent wing tucks somehow influenced its aerodynamics. So the team fitted the eagle with a customized, backpack-like harness equipped with a tiny, super-lightweight data recorder—actually a repurposed autopilot device from a drone aircraft. In this sense, the recorder served as the eagle’s black box, recording speed, altitude, pitch and roll, and a host of other information.

The researchers sent the bird on 45 flights through Brecon Beacons National Park in southern Wales, where they recorded 2,594 wing tucks. The data from their recorder revealed that the bird tucked its wings in response to atmospheric turbulence, according to the new study, published October 14 in Journal of the Royal Society Interface.

In other words, during pockets of bumpy air, the eagle’s wing tucks help keep it from crashing.

“When an aircraft hits turbulence, the whole thing moves. But a bird just tucks its wings and keeps a pretty smooth flight,” said study senior author Graham Taylor, a biologist at Oxford University in the U.K.

Continue Reading.

Any time there is relative motion between a solid and a fluid, a small region near the surface will see a large change in velocity. This region, shown with smoke in the image above, is called the boundary layer. Here air flows from right to left over a spinning spheroid. At first, the boundary layer is laminar, its flow smooth and orderly. But tiny disturbances get into the boundary layer and one of them begins to grow. This disturbance ultimately causes the evenly spaced vortices we see wrapping around the mid-section of the model. These vortices themselves become unstable a short distance later, growing wavy before breaking down into complete turbulence. (Photo credit: Y. Kohama)

Is there a period in human development when we have a “teenage brain?”

That’s a great question because there is even the issue that has been raised as to whether adolescence is “for real” in a biological sense. I mean, there’s plenty of cultures where essentially, you know, you’re married off to somebody when you’re 13 or some such thing, and all you are is like an adult with acne, that it’s not a special stage. And the suggestion that this is something that the West kind of invented, dealing with the fact that there’s now viewed as a delay between when one starts one’s main occupation, when one finishes education, and at the earlier end when the hormones start. Ah, we’ll call this magical period in between adolescence. So if it’s just an artificial construct, everything the brain is doing during development should just be in a smooth curve like this, where somewhere arbitrarily oops, that’s what we call adolescence is starting. Made-up concept. But that’s not what you see, because it is distinctive.

Parts of the brain are pretty much going full bore by the time you’re a year old, 5 years old. There’s parts of the brain, the limbic system which is involved centrally in emotion, which are pretty much all there by the time adolescence is starting. Then another distinctive feature of adolescence, which tells you it’s not just this: The hormones start. So what’s the frontal cortex doing there? The easiest picture would be if it’s the one that’s just sluggishly going on. That’s not what you see though. Interestingly, by the beginning of adolescence your frontal cortex is bigger than it’ll be as an adult.

Turbulence (Acoustic)
  • Turbulence (Acoustic)
  • At The Skylines
  • Empire EP
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At The Skylines - Turbulence (Acoustic)

Was I a part of you? Were you a part of me? 
Time and time again we’re running on empty.
Was I a part of you? Were you a part of me? 
I’m off this broken ride, I can see clearly.

Whoa, you lied from the start.
The sky could fall down, and you could never see it coming.
Whoa, take me back to the start. 
So I can turn around, and walk the other way.