What is a Hydraulic Jump?
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- čas přidán 1. 07. 2024
- Engineers need to be able to predict how water will behave in order to design structures that manage or control it. And fluids don’t always behave the way you’d expect. On this episode of Practical Engineering, we’re talking about one of the most interesting phenomena in open-channel flow: the hydraulic jump.
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Writing/Editing/Production: Grady Hillhouse
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I'm a contractor. My current job is replacing a hot tub built into a basement remodel thirty years ago. With no room to bring in a new hot tub I suggested a whirlpool bath, an idea the client accepted. The biggest problem was that the hot tub had no drain, water was pumped into the adjacent shower pan when it needed to be refreshed. To overcome this I built a platform with the drain running between it and the concrete floor, through the shower wall, over the top of the existing shower pan.
I was worried about water velocity because of the 20" head pressure. The drain leaves the tub with 1.5" PVC into a trap then travels at a gentle slope, 1/2" in four feet. As it enters the wall it steps up to 2" then flows out of a 3" shower pan drain with grill that is acting in reverse, water coming out horizontally instead of entering vertically. The volume is very impressive as is the sound. It is dispersed enough that it does not splash excessively, I think the grill helps a lot. I was quite pleased.
Here is what I did not expect. The flow from the 1.5" pipe overwhelms the 2" shower drain. Water depth in the pan gradually increases to about 3", near overflow. Then the most remarkable phenomenon and the reason I write. A tremendous whirlpool is created at the drain, 3" deep 2" diameter. No water goes down the center of the drain. By coincidence I am reading a book "The Science of Leonardo". He would have loved it. With the ceiling light of the shower shining through the turbulence the patterns are stable and clear.
I will cut a rubber washer to insert under the "popup" to reduce the flow. I think that will do the trick. We'll see. Thanks for your excellent videos.
It would actually be cool to see a video of this if you managed to record one.
We also observe hydraulic jumps in atmospheric science. They often happen downstream of mountain rages when mountain waves break. Super critical flow trapped above an inversion layer can transition to sub critical and cause deep mixing of the boundary layer. This mixing transports high winds to the surface in addition to the turbulence being induced by the terrain. This can lead to intense downslope windstorms also called chinook or fohn winds. Where I work in Wyoming, we often see wave breaks and hydraulic jumps produce damaging wind gusts over 100 mph.
How is sub and supercritical flow defined for air?
@@trucid2 essentially the same way as explained through here. Air is a fluid so it behaves the same as water or other fluids but with different viscosity.
@@TwisterKidMedia He defined it in terms of wave speed. How would that work for air?
@@trucid2 Never heard of supersonic storms before? 😂
@trucid2 Wave speed is just the speed at which a longitudinal wave (such as sound) travels through a fluid. This speed is generally constant for a fluid. What changes is the speed at which the fluid itself is flowing. So if air were moving very quickly at a place and then coming to an abrupt halt, that place would have a hydraulic jump of air.
"I owe me marriage to VPNs"
Okay hold up where is this going
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This channel is absolutely fantastic. I know a lot of what you go over, especially with fluid-dynamics, but you always have some little known information. My favorite was the concrete episode. Keep it up man!
When I found this channel I was binge watching his video it one of the best educational channel out their
I know nothing about any of this, but still find it super fascinating!
pererau Same here
Absolutely one of the best channels on CZcams!
remember to like and comment to help with the internal algorithm and help grow his channel :P
well one of the best engineering channels.
Practical Engineering and Smarter Everyday are my two favorite mind engaging channels. It doesn't get any better than these😃
Practical engineering and mark Rober are some of my favorite CZcamsrs
@@Kansasavation me too! I’m very interested in engineering, architecture, and science
I used this video as reference
with my customers who have issues with flooding basements.
By creating a hydraulic JUMP at the base of the roof's gutter system's down spouts, we achieved sucess by eliminating scour, with out digging a complex underground drain system.
THIS CHANNEL HAS EXTREMELY HIGH QUALITY CONTENT. MY CUSTOMERS ARE DELIGHTED.
Very interesting indeed! Thanks for posting.
Yo what’s up
I’m subbed to you
Perhaps you could show a study of the dangers of low head dams?
The drowning machine!
An intresting video presentation by Ed Kern from 2013: "Fatal Currents - Low Head Dam Presentation" (czcams.com/video/XsYgODmmiAM/video.html)
Especially since he mentioned how some rec facilities use hydraulic jumps. Makes me nervous to think of some dumb amateur kayaker looking for a spot of turbulence for fun. Designed facilities are not the same thing as found facilities, folks!
@@msaynevirta Thank you for the link. This video definitely reminda me of that presentation.
Also known as a weir
Fascinating. I got absorbed into the video and ended up in a calm place (the atmospheric music and friendly manners helped a lot). Thank you grady
In the process of researching the failure of the Oroville dam's main spillway in 2017, I read up on the earlier 2009 failure of their River Valve Outlet System, which involved a hydraulic jump. Their RVOS pulls water from the lowest/coldest point of the reservoir where it flows through a tunnel to a point under the dam near the turbine outlets (head pressure at about 300psi), and then can be released through a cone valve into another long tunnel that is joined by water from the turbine outlets (the tailrace). RVOS is designed to maintain minimum flow in the river when the reservoir drops below the turbine inlets and to regulate temperature for fish in the river. Oroville's Hyatt power plant is a pumping power station so the turbine outlets are submerged in their own trailrace which can either flow out into the Thermalito Diversion Pool, or pull water back from it when the turbines run as pumps. The tailrace consists of two 35ft diameter, 2000ft long tunnels. One is fully submerged, the other half full and they're cross joined. RVOS cone valves output into the half full tunnel at *extremely* high pressures and flow rates. Normally it blasts the water onto an angled steel dispersion ring which absorbs the high velocity flow from the valves, to merge it more smoothly with the low velocity flow of the half filled tunnel.
The ring had been damaged due to many years of use so earlier in 2009, they removed it.. (presumably with intent to replace). Then a few months later management thought it would be interesting to conduct a test to open the RVOS valve to 100% to see what effect it would have (1. they'd been told never to run it at 100% due to prior damage 2. design specs said RVOS was never to be operated without dispersion ring). The manually operated control (just a big wheel) for the RVOS cone valve sits in a chamber connected through a long person tunnel up into the inner turbine room, and that chamber is separated from the ring valve outlet by a fully sealed 20ft tall steel wall. That wall was designed to fail with 15ft of head pressure behind it in the unlikely event that the manual control valve failed and let water into that chamber. This wall failure would prevent water from backing up the person tunnel into the turbine room.
So.. 5 people enter the control room, and start to open the RVOS valve up to 100%. At 85% all hell breaks loose. The valves release about 4-5K CFS of water at extremely high velocity into a half filled tunnel, and without the dispersion ring this accelerates the velocity of the water in the tunnel for a few hundred feet. During original design (including extensive small scale testing), they realized that even with the dispersion ring a hydraulic jump could form as high velocity flow meets low, that might reach up to the roof of the tunnel, which could cause a vacuum condition in the tunnel upstream of the jump. So they built in a vent in the roof several hundred feet down the tunnel connected by a large tube running back to another vent in the cone valves outlet chamber. Idea being that if the jump formed between the two vents sealing the tunnel it could still equalize the air pressure on either side of it. But without the dispersion ring in place, the jump moved much further down the tunnel than design called for, and blocked the lower vent. This caused a siphon pump effect back to the valve outlet chamber, eventually causing high enough vacuum that the steel wall designed to hold back 15ft of water, blew out into the tunnel almost taking the 5 people in that chamber with it. Doors further up the man tunnel also failed and debris was sucked down that tunnel pelting the people in the chamber now open to raging water and continuing vacuum. With hurricane force winds coming from the person tunnel through the chamber into the RVOS outlet someone managed to turn off the valve to stop the flow. One person was seriously injured. RVOS was repaired in 2014, and operated again that year when drought conditions dropped the reservoir below the turbine inlets.
:O ......
Why tho? Why did they want to try that?
So what consequences did management face for reckless endangerment of 5 lives? Let me guess... a raise, promotion, transfer, or all three of the above.
@@allencummings7564 Short answer. They're idiots. Long answer according to the investigative report afterwards.. ""DWR removed the baffle ring in April 2009, four months before the test. It did so without consulting its Division of Dam Safety, which should have approved that action first. The test was ordered because DWR “wanted to determine the destructive effects” of opening the valves to 100 percent, according to the investigation."'
Mission accomplished.
Military application then?
And yet again, you post a video that makes supposedly complicated and abstract things so easy to understand. Brilliant! don't stop being you and amazing. x
I will respectfully watch every single ad and like all the videos, I absolutely love your content and you deserve all my support! Thank you for this amazing knowledge and thanks to you I am walking down a Engineering path!
Absolutely love your videos and how you make civil engineering so fun! Keep up the good work! Cheers!🙂
Everything you publish is first class. You can really communicate the concepts to people. It's geeky, but makes me proud to be an engineer. If these were shown to high school students, they might choose different fields of work that make them happier. Kudos to you!
I don't general comment on videos but I wanted to say how much I love how you handle your sponsorship ads. They don't interrupt your videos and are extremely well done and to the point. I even found myself watching them and I am even considering getting VPN just to support you. You sure as hell deserved it.
Thank you and keep up the fantastic work!
Another great video! The only thing I would have added is a little discussion about what the Froude number is in various flow regimes. It would be useful for Civil students and others interested in understanding these things.
So, how do they prevent the hydraulic jump structure from eroding?
Make it out of concrete ;)
I would imagine (in a dam example) that because the slipway and hydraulic jump section is generally exposed or near surface close to the dam, it is easy to work on it there and maintain or replace damaged sections, rather than trying to repair erosion downstream.
I suppose that, since the structure is already in that turbulence zone he is talking about (since the hidraulic jump starts ahead of the structure), the effects of the erosion had already stopped being important before that structure.
@@Fuyudo Concrete is not that resistant to flow erosion. Cavitation can break it very easily, even metal.
I think engineers would take that into consideration
One of the very few channels that favor quality, not quantity.
This is really interesting!! I love how you explain things!
Very enjoyable. No flashing images and loads of crappy music - just the facts and a practical demo. Thankyou!
Grady the type of guy to make a 100% overlooked phenomenon interesting and accessible.
normaly I would skip this video because the thumbnail couldn t get my attention but then I realized its a practical engineering video. Good work👍
Well, better that than emojis and OMG slapped all over it. I hate that crap.
Great info, well-presented - thank you
Fluid dynamics is my fav subject and this video just incredibly made me more interested towards this subject. Thanks a lot.
I thought rocket science was like 90% fluid dynamics. Moving metal thing through fluid (atmosphere), controlling and directing flow of fuel.
There's also a lot of material sciences involved.
From what I can tell, the main difference is the density of the fluid medium. The principles seem the same, they just happen at much lower speeds in water.
@@mikecurtin9831 water is also essentially incompressible
Moving stuff through fluids is aerodynamics, fluid dynamics deals with the motion of the fluid itself iirc. But I guess they're close enough.
And physics
0:12
Right side: Lvl 1 turbulent flow
Left side: Lvl 100 *L A M I N A R F L O W*
_That's how fluid dynamics works_
I see you are a man of culture as well.
you deserve a medal
Lol have you been watching SmarterEveryDay?
Pewdiepie ft. Smarter everyday
Oh yeah yeah
I'm a kayaker and I clicked on this video because it reminded me of rapids and whitewater in rivers and then you explained it and even mentioned how we kayakers use this physical phenomenon to have fun! You explained it perfectly! Great video!
one of the coolest videos on youtube. This video started getting me interested in fluid dynamics!
“. . . So I built a flume in my garage!” Is one of the nerdiest exclamations I’ve ever heard.
Fluid dynamics = "My feet slowly got wet."
Rocket science = "Big tube go real fast."
Got it. :)
This was my favorite subject in civil engineering classes - hydraulics and fluid mechanics.
Love the way the information is presented
support your teachers. it's hard to find great teacher
1:14 A nightmare for my over imaginative mind.
yeah, can you imagine standing on that catwalk looking directly down in the maw of that thing. geez.
Nope to the power of nope, noped.
You hit the nail on the head, nice to know I'm not the only one. I think my heart stopped & my mouth opened. What if? What if? What if?
Come on Georgie. We all float down here.
Same here. If you're feeling adventurous, check out this video. It starts out fascinating, but wait for what happens after the cameraman zooms onto the stairwell a couple minutes in: czcams.com/video/fJVBlhgt9j8/video.html
It's during a regular test that shuts a valve near the turbine and what you see is holding tank to prevent a water hammer (which can cause damage to the water tunnels) from forming when the water tunnels to the turbine are closed. The uploader works at that dam, so check out his other videos, including down that hole on the right and a device (located up the incline) that is lowered down it to remove/replace the turbine blades.
Awesome video, actually learned something that they didnt teach me in a fluid dynamics course in engineering school. Keep up the good work.
Fascinating. thank you. I have a white water centre near me in Nth london and on my visits observing the canoeists i noticed that when exiting a 'rapid' they actually stayed where they were and didn't get pushed downstream. I was puzzled. I found your video and it goes some way to explaining why. Thanks again.
When you see ocean waves coming on shore and then retreating, you can see a 'battle' between the receding and approaching waves, as mentioned in the video. Is that also a hydraulic jump? If yes, which is the tranquil bit and which is the fast bit?
Smarter Every Day channel talked about "laminar flow" this week, youd appreciate the video😎👍
I thought it was suspicious as well.
You give so correct practical knowledge
You make engineering fun! Keep it up 👍
Being a civil engineer, I wish that you would have been my teacher in my college days😔😔
At 01:15 what dam is that? Never seen it before and I love dams.
studinthemaking Right?! That's pretty gnarly looking.
Completely perfect demonstrations !!! Thanks.
Tashkent, Uzbekistan.
The best and most useful channel on youtube PERIOD.
Neat
Me: Lord, bless me with sleep at 03:45,
CZcams: Tenuous engineering tutorial..?
Me: I’ll sleep when I’m dead; CZcams; teach me.
Your channel is absolutely incredible. Keep up with the fantastic videos!
Love your work! One of the best educational videos around!
In rocket science, there is a perfect analog: the shock wave. It also forces flow to go from supercritical to subcritical.
1:11 You mean like the Oroville Dam?
Love the visuals you make. Thanks
Thanks, you've got an absolute gift for explaining engineering theory clearly and concisely.
Where is the dam from 1:11? :o Looks amazing, never seen such before
Huia Dam, perhaps. That's a bellmouth spillway.
What a complicated way to say "the water piles up against an obstacle"
Right. Like I said, it's intuitive and easy. This video tries to make it seem like something surprising. There are a lot of things in physics that I do find surprising. In fluid dynamics, I'd go with the Venturi effect and Mach diamonds. Elsewhere, gyroscopic precession, quantum locking. But this video spent nine breathless minutes saying "water piles up and the slow part ends up on top."
This is really well done. Thank you! I've been in CE for a while and I always learn a thing or two in your videos. Here are a couple video ideas that I would like to see: water/wastewater treatment, hydroelectric power, truss vs arch vs suspension bridges, and the diverging diamond interchange.
Love your videos, Grady! Thank you for what you do.
Does anything special happen when the flow is exactly critical or very close to it?
The height of the water becomes very variable.
Critical flow is also a very unstable condition that engineers seek to avoid when designing channels. You would ideally design the channel so that either the sub or super critical flow dominates, because as you approach critical flow conditions, the system as a whole becomes increasingly unpredictable
@@villageblunder4787: Thanks. It'd be interesting to see what that looks like.
Those hydraulic jump spillways are also really dangerous. Not always a good compromise.
He was referring to dams with dissipation on the downstream side which prevent an abrupt hydraulic jump and prevent a retentive hole from forming to avoid erosion (and avoid a severe drowning hazard)
Tilman Baumann yep i almost died in one. glad i have an inflatable boat and not a canoe. see main comment for more info.😩🍻
You are the best! Explanations as vivid as these should be mandatory in fluid dynamics classes.
I'm really enjoying your channel. I've been interested in infrastructure designs ever since I was a little kid. So, thank you!
hydrolic jumps are also super dangerous please mention that somewhere before people drown while trying it out in a kayak
We have plenty of people. We can afford a few deaths by hydrolic jump.
If people want to nominate themselves for a Darwin Award, that's their business.
TheKazragore yeah well... I wasn’t aware that these were dangerous before a few years ago, they seem not completely friendly, but they are far more deadlier that they actually look... once you get stuck in one, you don’t get out
All kidding aside, the dangers of hydraulic jumps are not immediately obvious, and many of those killed are rescue personnel and even those trying to recover the bodies of rescue personnel.
As I'm seeing it, knowledge of what's happening mitigates most of the danger. Like with rip currents; for scuba divers they're a free ride out. The difference between safe and not is in recognizing and understanding what's going on. Without trying to be judgy, what makes things dangerous is ignorance and stupidity.
We need to get this channel to atleast a million subs
A Mechanical engineer
Really nice explanation of the jump. I 'm an engineer for NJ and our erosion control program (urban; construction, storm water etc) deals with scour protection all the time. I'm going to forward a link to your video to our soil conservation districts for them to watch!
Very nice video.
That's how I've learned it for many years in hydraulic and coastal Engineering
Greetings from Germany
in munich people surf the eisbach, i guess thats the same principle there
ok. but when comes HL3?
watching this video made me thirsty.
also watching this video made me realize there is soooooo much water on earth.
thanks you veruy much for this contribution, it is a great help to understand better the open channels flow
Excellent demonstration and discussion, now my sidekick is pondering ideas for other ways to reduce water velocity.
Very interesting engineering... definitly not duboius! :-)
"Unlike rockets, you might have some intuitions about-"
Uh m8
You think I haven't played Kerbal Space Program?
Man, i really love this channel. You are the best channel about engineering. A big shout out from Argentina!
Fantastic video!! Thanks for sharing 😃🙌🏻
1:20
Now, I'm not that young, and i don't know all the cool lingo the kids are using these days but I think it's fair to call that a #NOPEHOLE
69adrummer oww
Intro music ???
Thanks for the explanation!
fantastic script & demos!
Can someone please tell me where 1:12 is??😍😍
I want to know too.
Lower Huia Dam near Auckland, New Zealand. Found this in another post and verified with a Google search. www.cs.auckland.ac.nz/~bwue001/Tramping/LowerHuiaDamCircle/LowerHuiaDamCircle.html
I have seen a couple others too .... usually with some sort of fence to keep people out
No way, 5:01 is way better. 😍
I'm thinking of being a civil engineer when I'm older but I don't know what qualifications I need
Please like this so that he will see it
Great videos sir. I'm glad I discovered your channel.
You're amazing! Am currently doing my MSc on Engineering Geology. Your videos are very informative and educational relative to my degree. Thank you!
I can't see the whole shirt, but methinks Grady is representing the HSV. ThinkerCon swag?
If you are looking to get married you should probably get a VPN...
Lmao upvoted, dude
Feynstein 100 “Upvoted” Ah I see you’re a man of culture as well
How relevant haha
Great video. I just took my Fluid Mechanics course and am now taking Environmental Engineering course and this video was a great explanation of sub/super critical flow. 👍🏽
excellent explanation of a concept ive been wondering about for some time
This video would've been sooooooooo helpful during my 6th semester of college 😂
Interestingly, you show us a hydraulic jump, but you never actually define what it is.
@Sunyata I know, but here again you also fail to explain what the 'jump' is. If you're going to try and explain something, maybe stand back a bit and look objectively at what you're saying. It's called a 'jump' because the surface level of the water just beyond the flow intersect is HIGHER at the sub-critical flow rate than it is at the critical flow that feeds it.
101
Nice presentation. Now, if I have an informed understanding of the subject. Thanks.
Thank you for making these videos. Please keep up the good work!
"Fluid dynamics might sound as comlicated as rocket science..."
Boy i wish it was. Rocket science is weak shit when compared to fluid dynamics.
There's a reason why theres still a Millenium problem open on the Navier Stokes equation.
"I owe my marriage to VPN..."
The way of teaching is amazing & as per requirement & almost excellent!
I wish I had you as my physics instructor in college. You explain things extremely well....great series of videos......
You know it’s that time of the month when your girlfriends flow goes from subcritical to supercritical
MidNight DarkChocolate LOL
Perhaps you should make her jump too ;)
Feynstein 100 Watch out for erosion tho
Tampons are the ultimate hydraulic jump
Umm, wouldn't that just cause the flow to be a lot heavier? I think supercritical would not be too bad to deal with.
Nord vpn.....?????
Naaaahhhhh
I like nord lock washers
Two months of fluid dynamics course packed into 8 mins! Thank you very much for this.
Man, you create amazing content. Thank you for all your hard work.
Your Videos should be longer 😌
Laminar flow all the way.....
edit: omg... so many likes.. Thank you ... this is my most liked comment so far.... Heil Laminar Flowwwwww...
SmarterEveryday hey 😉
@@USSAnimeNCC- who dis? ;)
LAMINAR FLOWW
@@robertw6894 Party Trick and Natural Beauty ⛲
Destin agrees
czcams.com/video/y7Hyc3MRKno/video.html
What a coincidence! I was just studying about this topic and you posted this video. Thank you
Please cover more hydraulic structure and fluid engg :D
I love seeing how the quality of these videos have improved very nice