Forming Granular Plugs
Imagine filling a narrow tube with a mixture of water and tiny glass beads. Then take a syringe and very slowly start drawing out the water. As the water gets sucked out of the tube, air will be pulled into the opposite end. The meniscus where the air and water meet sweeps up the glass beads like a liquid bulldozer.
As the experiment continues, pressure builds up and air starts filtering through the beads, changing the viscous and frictional forces the system experiences. Eventually, the grains break off, leaving a chunk of glass beads – known as a plug – behind. Keep draining the tube and more plugs form.
Watch video:
www.youtube.com/watch?v=PYYnfKUddro
Paper:
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.028002
Source:
https://physics.aps.org/synopsis-for/10.1103/PhysRevLett.117.028002
h/t FYFD
#physics #granularplugs #experiment #research #science
This is super interesting. I wonder if you could prevent plug formation by pulsing the drain suction or reversing the flow briefly.
ReplyDeleteI'm surprised this is news and wondering what they're trying to learn, discover, fix, or invent?
ReplyDeleteBryce Etheridge Interesting question. I think the answer is probably 'no' because, after looking at the vid far too many times, I think the critical factor eventually is the difference in frictional resistance which is greater at the bottom of the tube compared to the top. That is because of the wait of the sand of course.
ReplyDeleteMind you it might work with ultrasound! ??
physics, ok, and there's nothing alive in the observed experiment but don't plugs have biological relevance otoh?
ReplyDeleteThis work may lead to a better understanding of other fluid-grain flows, like, for example, the hydraulically driven flows of ingredients found in the pharmaceutical industry. ann kiszt
ReplyDeleteThanks for the explanation, Corina, I get it now.
ReplyDelete