What are DROWNING MACHINES?

as the administrator of a large underground facility filled with dangerous machines and laboratory equipment and non-euclidean organisms that defy traditional classification i'm very familiar with very scary warning signs don't worry about that if you need an anti-matter reaction warning sign or a non-standard space-time sign you can be sure and you might get into something pretty harrowing around here but by far the scariest warning sign that i've ever seen outside of these walls has to be this one what exactly is the drowning machine now entering the facility if you were to walk along the shore of one of the many rivers in the united states that has a dam within it you might encounter a sign like this and no it's not a joke or a photoshop or a plant a drowning machine is a real if bit dramatic engineering term that describes one of the worst water-based situations you can ever find yourself in now to understand why a sign like this is absolutely necessary we have to begin with flow and no not the flow that you hear on your radio thank you arya i know that was embarrassing i mean flow like moving liquid like water now one of the ways to categorize the flow of water would be to see how waves move within that flowing water now that sounds a bit esoteric but you're already familiar with this distinction in air when something is moving slower than waves do in air we call it subsonic when it's moving faster than sound waves in air we call it supersonic and when something is such a bad character design that it costs a movie company tens of millions of dollars and endless internet outrage we call that sonic the hedgehog similarly when water is flowing slow enough for waves to propagate through it like throwing a pebble into still water it is called subcritical flow and when the water velocity surpasses the wave velocity so waves can't move through this fast water it is called supercritical flow we already looked at a fascinating example of this when we created our very own sonic black holes in a previous episode the event horizon in the bottle that we looked at was the boundary between sub and supercritical and like the sonic black hole what interests us today is again that boundary where different flows meet think about what would happen when very fast moving water smashed into slow flowing or even stationary water you'd think that all that kinetic energy has to go somewhere and it does when super meets sub kinetic energy is transformed into potential energy as the water bunches up and rises in what's called a hydraulic jump this is the equivalent of a sonic boom in air but this boom in water is very impressive risings of the tide so to speak you can see it in large dams and rivers but you can also see hydraulic jump in your sink probably the quickest and easiest way to see a hydraulic jump is to simply go to your sink after finally putting away the dishes like you said you're going to do last week and turn on the faucet now watch the water see that little circle that forms right here now you've probably seen that circle form thousands of times without thinking twice about it but this is indeed a hydraulic jump well why does it form here well once a film of slow moving subcritical water forms the bottom of the sink it's still encountering the fast-moving supercritical water from above the boundary here is where all that kinetic energy is being dissipated cool right administrator yes arya what has ignored the self-replicating machine's warning signs viewers please enjoy a short commercial break i have something uh apparently very important to handle oh my science there everywhere was that goo a person where's kevin no they're dismantling the lab oh arya engage countermeasures they are not responding to the speech what do you mean they're not responding to the signal get them contained now my leg oh no it's fine you're fine you just saw someone get molecularly melted from the inside out it's not going to scar you for life it was good coffee though oh i'm sorry what were we talking about it seems kind of dumb now what with all the death oh hydraulic jumps hydraulic jumps are the operative mechanism in the drowning machine but we need a bit more fluid dynamics before we fully understand them you see depending on the conditions a hydraulic jump can happen at different points observe this first yield de-engineering graph in this graph you see some supercritical water spewing out from some opening and it's encountering water downstream that doesn't really have any hindrances to it so the water does exactly what it wants to do and jumps up perfectly according to the conservation of momentum in this second figure you see something different happening beyond the supercritical flow there's some change in the water that allows it to flow more freely than it otherwise would maybe a change in slope and so the jump occurs much further out from the boundary point now look at this third figure something downstream of the supercritical flow is impeding the flow like debris or maybe even another dam this pushes the water actually before where the hydraulic jump forms the hydraulic jump is now under water forming what is called a drowned jump this is the killer component since 1900 there have been more than 700 documented drowning death in the united states at what are called low head dams and since 1900 the death rate has accelerated why these smaller dams just happen to produce the perfect hydrological conditions to produce the last diagram that we looked at drowned jumps right past the point where the water drops just a few feet off the top of a low head dam a drowned jump forms beneath the surface of the turbulent water but the jump itself rises further away from the dam where the water looks like it's boiling this creates a recirculating flow a kind of vortex water is deceptively heavy and heavy water flowing quickly can be extremely forceful the vortex that can form on the other side of a low head dam can therefore trap smaller objects within it indefinitely in a never-ending cycle washing machine like of submerging the water is usually freezing cold making hypothermia a real concern it's turbulent and full of bubbles making it less dense and much much harder to float in even if you're wearing a life jacket these vortices contain tumbling logs and debris and trash that will bludgeon anything that comes into contact with them forever put all this together and indeed you have if you're unfortunate enough to fall into one the perfect drowning machine these are so dangerous that not only are there warning signs everywhere about them it seems that almost every state in the us has some pamphlet or video about the dangers there are thousands of low head dams across the united states many of which are unmaintained or abandoned service please arya so these signs are absolutely no joke the dams that harbor these hazards are extremely hard to see if you're on the river so they can hit you without warning and if you were to fall into a drowning machine it's almost impossible to save you i'm not exaggerating you are advised against trying to help someone who falls into a drowning machine without proper training and equipment just a life jacket won't cut it and i need to say that because unfortunately a number of would-be rescuers even professionals like firefighters have found out the hard way look kayaking and tubing and other summertime activities that your friends who wear birkenstocks all the time will peer pressure you into are very fun just be safe out there and heed any scary warning signs that you see they're scary for a reason and nothing nothing is worth meeting the drowning machine until next time now exiting the facility thank you so much to the vera nerdy staff at the facility for their direct and substantial support in creating this video today especially i want to recognize research assistant digital neo whoa and visiting scholar chris onyx cool name that i didn't almost forget if you want to join the facility staff today if you want to join the nearly 1200 nerds that are giving me episode ideas and talking with each other working with their own game nights and dnd remotely and listening to a music bot that kind of works sometimes you can go to patreon. i know it sounds fun you can go to patreon.com kyle hill and sign up right now to get on the facility staff today and if you support us just enough you'll get your name on ari here each and every week and as you can see there's more and more of you each week so i don't really know how to pass the hydraulic jumps aren't evil it's just in low head dams they just happen to produce something that is very dangerous but uh usually engineers will use hydraulic jumps to their benefit they're very good at dissipating energy so with something like a dam you can do clever calculations to figure out how far you want the jump to happen how high you want it to be and that can dissipate 60 to 70 percent of the water's energy which can keep the sub critical super critical boundary from destroying your structure or eroding the river better or what have you how long i've been talking for jeez there's a lot of you thank you thanks for watching bye

Channel: Kyle Hill

Views: 1,886,328

Rating: 4.8933973 out of 5

Keywords: because science, engineering, kyle hill, learning, math, physics, science, stem, the facility, drowning machine, dam, low head dam, civil engineering, dangerous, kyle hill channel, rokos basilisk, kyle hill magic the gathering, kyle hill basilisk

Id: KaeqEVI0uCk

Length: 9min 56sec (596 seconds)

Published: Fri Jul 31 2020

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edit: nvm I misheard "self-replicating genes" for "self-replicating machines". makes more sense now...