Researchers crack an enduring physics enigma

Phys.org ^ | Ecole Polytechnique Federale de Lausanne

[BenLurkin]

For decades, physicists, engineers and mathematicians have failed to explain a remarkable phenomenon in fluid mechanics: the natural tendency of turbulence in fluids to move from disordered chaos to perfectly parallel patterns of oblique turbulent bands. This transition from a state of chaotic turbulence to a highly structured pattern was observed by many scientists, but never understood.

For decades, physicists, engineers and mathematicians have failed to explain a remarkable phenomenon in fluid mechanics: the natural tendency of turbulence in fluids to move from disordered chaos to perfectly parallel patterns of oblique turbulent bands. This transition from a state of chaotic turbulence to a highly structured pattern was observed by many scientists, but never understood.

The researchers combined...dynamical systems theory, with existing theories on pattern formation in fluids and advanced numerical simulations. They calculated specific equilibrium solutions for each step of the process, enabling them to explain the transition from the chaotic to the structured state.

In fluid mechanics, stripe pattern formation is important because it shows how turbulent and laminar flows are in constant competition with each other to determine the final state of the fluid, i.e., turbulent or laminar. This competition arises whenever turbulence forms, such as when air flows over a car. The turbulence starts in a small area on the car's roof, but then it spreads—because turbulence is stronger than laminar flow in this particular case. The final state is therefore turbulent.

When the stripe pattern forms, it means that the laminar and turbulent flows are equal in strength.

[Jamestown1630]

Well, I think it's likely that more than 10 per cent of the population could understand any 'esoteric' science, given the interest and desire to study and master the subject.

[Songcraft]

"When I think of the many nights I lay awake................."

:-)

(And this "fluid" phenomenon probably comes into play for some guys at night, as to whether their own fluid productions (on their trips to the bathroom on sleepless nights), display "disordered chaos" (random sprinkling), or "perfectly parallel patterns of oblique turbulent bands" (a steady, well-aimed stream that goes right where it's aimed).   This new discovery might have an impact on countless marriages around the world, as many wives have been known to frown mightily on the end results of "disordered chaos" in that particular fluid department.)

[BipolarBob]

George Costanza.

[Chode]

why the Russian aircraft designers don't bother with flush rivets past the boundary area where the laminar flow separates, once the boundary layer trips that's the end of laminar flow in that region... but then with the loss of laminar flow, non-flush rivets create drag

[Leaning Right]

> George Costanza <

I was wondering if anyone was going to catch that. Good work.

[Reily]

Source code or executable?
If source code just re-write in the code of your choice.
Slow but educational & more fun!

[kosciusko51]

Source code. You have to compile it and the supporting libraries to get the executable.

[broken_arrow1]

Don’t scientists have anything better to do?

[Red Badger]