For 141 years, physicists like Richard Feynman have puzzled over the problem of fluid flow. How do sprinklers spin when they’re underwater, sucking material in instead of spitting it out? Now, a team of researchers has found the answer.
The idea was first proposed by experimentalists in the 1880s, but was repopulated by Feynman in the mid-20th century and became known as: Feynman sprinkler. The problem is: A regular sprinkler with an S-shaped arm spits out water and rotates the arm to water what needs watering. However, whether reverse sprinklers rotate in the first place remains an open question, and not without trials.
Feynman considered this idea for a while, but We built an experimental device I answered this question while a graduate student at Princeton University. (The experiment ended when a large bottle of water exploded.)
Now, a research team at New York University has put it back together. The Reverse Sprinkler Redux (that’s what I call it, but it rolls right off the tongue!) consisted of a sprinkler submerged on “ultra-low friction” bearings. According to a release from New York Universitydesigned to easily observe the flow of water through the device to optimize the free rotation ability of the device.
To this end, the team dyed the water, added microparticles, illuminated it with a bright green laser, and videotaped the entire experiment with a high-resolution high-speed camera. The resulting image is quite strange:
Team research—published Last week’s Physical Review Letters found that reverse sprinklers do just that. It rotates in the opposite direction to the sprinkler that sprays water.
“Normal sprinklers, or ‘forward’ sprinklers, are like rockets because they propel themselves with a jet of water,” said Leif Ristlov, a researcher at New York University and lead author of the study. Ta. release. “But reverse sprinklers are mysterious because the water being sucked in doesn’t look like a jet. We discovered that the secret is hidden inside the sprinkler. There are actually observed There is a jet that explains the movement.”
Reverse sprinklers rotate in the opposite direction (checking notes), but the speed is approximately 1/50th that of regular sprinklers. Inside a reverse sprinkler, the sucked-in water streams collide with each other, although not head-on, and the water inside mixes, slowing down the rotation of the sprinkler.
Brennan Sprinkle, an aptly named researcher at the Colorado School of Mines and co-author of the study, said the method used in the experiment has “many practical applications, including devices that react to flowing air and water. It will be helpful,” he added.
Whatever the potential application, the challenge first posed in the 1880s has finally been solved through rigorous testing and modeling that would have been impossible 140 years ago. I hope this article inspires you to incorporate something into your next conversation about fluid mechanics.
more: A sprinkler that blasts intruders is an AI-powered replacement for an old man yelling at kids to get off his lawn.