Practical Engineering - 2019-01-29
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. -Patreon: http://patreon.com/PracticalEngineering -Website: http://practical.engineering Writing/Editing/Production: Grady Hillhouse Tonic and Energy by Elexive is licensed under a Creative Commons Attribution License Source: https://www.youtube.com/watch?v=U6fBPdu8w9U This video is sponsored by NordVPN.
There is a disappointing number of old Chevy Impalas hopping around a parking lot in this video.
No Olds Cutlasses either...
That comment was funny before I understood the double meaning of the title. I think it should be my standard comment to any video!
That took me a sec.... LOL you won the internet for a day with that comment
Mumbʟes005 I’m the 500th to like this comment. What prize do I get?
Taylor Humphrey you get this: https://tinyurl.com/dymbb3a
Perhaps you could show a study of the dangers of low head dams?
Bryan Dunn ...Thanks for the heads up. I watched it and as usual his explanation is second to none.
He's done it!
Well, he did that.
He's got one
Ha, I came here from that video.
Hello from the future
"I owe me marriage to VPNs"
Okay hold up where is this going
Thailand? Moldova?
Absolutely one of the best channels on YouTube!
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 Youtubers
This guy seems like Mike Judge character but the channel is pretty great, better presentation and production and content than anything on TV of the past.
You are one of the best commentors
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
So, how do they prevent the hydraulic jump structure from eroding?
@Skeptisk a very interesting idea. I don't know who you would bring it up to as someone to study the idea or feasibility of it's use. I will say this much, I worked construction years ago and did alot of underground work which included installing water main which usually ductile iron pipe which has a wiped on internally spun concrete lining inside of the pipe to I think protect the inside of the pipe from corrosion. It is not perfectly smooth though. Ductile iron is alot stronger than regular cast iron which was more brittle but was used farther back in history before ductile was invented. This type of piping is not limited to underground use. It is used in above ground pip g as well. Good luck in pursuing your idea.
Usually, they put up concrete aprons to prevent scouring, but considering the economic aspect, boulders and gabions may be used, voids will then be grouted.
@Fuyudo Yet hydraulic cavitation will destroy your concrete idea in a matter of hours if not designed correctly. Concrete is far from indestructible.
Of course to keep the hydralic jump from erroding we need to make it out of pure diamond. Problem solved.
Vicent Beltran Yup, avoiding cavitation is a major part of spillway construction.
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.
@Pavel Peřina Thanks, I read about boundary layer waves in "High performance sailing" by Frank Bethwaite. This video is perfect visualization.
@Twister Kid Media Wow, that sounds interesting. Are transverse waves even possible in a medium? I thought only longitudinal waves were. 🤔
I used to live in Utah close to the Wyoming border where HWY 84 goes up the canyon passing Sundance. The wind there was incredible! There were days of 30-40 mph winds with gusts up to 75mph and other days of 50-60 mph wind with gusts of 90-100 mph. I didn’t know plain old wind could do that. We even saw a few tornadoes including one that went through downtown Salt Lake City.
@Twister Kid Media That's pretty cool. I always like it when a scientist from another discipline is able to chime in on an unrelated video and connect it to something in their own field. Funny enough, it was a professor of mine from grad school who did that (brought in a theory from a completely unrelated field) which ended up providing me with the topic of my master's thesis.
Yes I agree, Air is very much like water when it " flows". Simple obstructions can cause great variations in pressure and velocities,.
Excellent video!! Did you ever learn something and, all of a sudden, you can feel 37 different things in your head all sort of fall into place, click together and a whole new section of that internal Big-Picture-World-View, that Reality Map that consists of every thing you've ever seen or learned, every truth you've uncovered or intuitively felt, that shapes and defines your understanding of reality, makes sense, and links are created between other things and now a whole myriad of ideas, truths and understandings, all make sense and are explained? That just happened here, with this video, and it's honestly one of the greatest gifts I think one person can give to another. Thank You for making my world make more sense and my understanding of reality more complete and correct. I gotta watch this again now
@H S Sanjay bro if you want to comment then learn how to type
@senpai mind ur business nosyhead
@Nick éS Talk about collective thinking!
Ryan Smith
Inly when I drop a hit if acid and listen to the Grateful Dead
Indeed Ryan Smith and your comment contributed to that for me personally! ^^
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
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
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
This dude is smart. Why aren't engineers politicians they actually fix real problems
@Q 400 engineers > scientists
Simply elegant models. Well done sir.
Why is politician a career?
Tjey make crappy presidents. Herbert Hoover
@Tubmaster 5000 Yes, very successful engineer. Very poor president
"Unlike rockets, you might have some intuitions about-"
Uh m8
You think I haven't played Kerbal Space Program?
Smarter Every Day channel talked about "laminar flow" this week, youd appreciate the video😎👍
I thought it was suspicious as well.
Me: Lord, bless me with sleep at 03:45,
YouTube: Tenuous engineering tutorial..?
Me: I’ll sleep when I’m dead; YouTube; teach me.
1:14 A nightmare for my over imaginative mind.
Where is that place at 114??? Thats incredible.
@crowtrobot313 aerial shot of the spillway of a reservoir dam in Auckland New Zealand
https://www.videoblocks.com/video/aerial-drone-of-spillway-in-a-reservoir-dam-in-auckland-new-zealand-h02xdztfzjey4brbm
Just in case anyone wants to look into the spillway :) https://www.youtube.com/watch?v=e2b8LC-TKFw
@Krishan Bhattacharya thanks! I missed the reply. I appreciate it.
Forbidden slide
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.
@Allen Cummings California has a lower average IQ than Alabama. It ranks #48.
When you read the various reports on Oroville, it's as if they were actively trying to destroy the dam through malicious incompetence on numerous occasions.
~95 - ~105 .... Not sure why it would be relevant to begin with, but certainly a tiny range of ten points is entirely irrelevant
And then you've got "malicious incompetence", that's interesting .... Malicious would be purposeful wouldn't it?
Did you watch blancolirio's videos on the dam failures as well?
@SlocketSeven That's cute, you think you know what you're talking about.
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.
@Mike Curtin 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
Glad to have a civvie who can explain open channel flow to this mechie. I've had a few false starts on reading up on hydraulic jump, but never really got anywhere. I've seen the sink example, but it didn't really give great insight like tying in subcritical and supercritical flow.
Also, I definitely experienced some low-key anxiety from the shot of the bellmouth spillway with the viewing platform right over the middle. Nothing like rolling a little acrophobia, bathophobia, submechanophobia, and a residual childhood fear of drains all into one! I also feel completely compelled to visit someday ... where is it?
I'm not sure I got all of this on first viewing because there're many things going on, including sub- and super-critical flow, upstream and downstream control, wave speed vs flow rate, hydraulic jumps, turbulence, and erosion. I think not all of these need to be here, and (since they're all interrelated) the order of presentation should be different.
You start with wave speed vs flow rate, and define criticality from there. Could you define criticality some other way? You never go back to wave speed. It seems -- I'm unfamiliar with a lot of fluid dynamics -- that subcritical flow is laminar, while supercritical is turbulent,and I think that might be a better place to begin.
I enjoy your series, and always look forward to new videos. Keep 'em coming.
0:54
Actually I have a great understanding of rocket science but not fluid dynamics. Thats why I'm not watching scott manley right now.
I love this channel. Wish I knew it when I was a college freshman in civil engineering. Already a senior gonna take hydraulics next semester!! Great introduction for what I'm gonna head into.
"struggling waters are the hydraulic jump" am i right
07:03 You might not wanna ecourage ppl to go near "hydraulic jumps" and being pulled down as you mentioned in another video.
Very interesting indeed! Thanks for posting.
Just learned im accepted to master degree for deparment of hydraulic 🤷♂️ this video came right when i learned it
Wow, this is the first time I watched an ad to the end. You gave it a personal touch. It's a romantic story of its own with an exposition and denouement :)))
Ahhhh I've missed your theme music. Happy 2019 Grady and fam!
I was at the beach yesterday and a weird wave went past (through/around) me, which I wondered if it was a hydraulic jump wave (I'm guessing just a moving hydraulic jump). It was a turbulent wave without the possibility of breaking as it didn't have the right conditions.
The furthest waves were about 3m tall, the ones we were catching (boogie-boarding) were about 1-1.5m tall. Maybe 5m in between breaks (as in rip curls/breaking waves). There was a rip (current) moving sideways at quite fast speeds and not all waves were coming in from the front. I'm in Australia.
"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.
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.
The other day I farted and I'm reasonably sure there was some degree of hydrologic jump.
What I find very interesting is how certain aspects of environmental regulations (buffers around ponds and streams) have discarded what is BEST for long term erosion control, safety, and ease of maintenance in exchange for some more “eco friendly” solution. For example, nowadays concrete flumes into ponds are not allowed in many jurisdictions.
One of the very few channels that favor quality, not quantity.
you should do a video with @SmarterEveryDay I just finished his video on Laminar Flow!
“. . . So I built a flume in my garage!” Is one of the nerdiest exclamations I’ve ever heard.
Yeah, I'll keep an eye for supercritical flows from now on. Thanks!
I live around 300m downstream from a dam, I can see it every time I go out to the backyard.
The water level rises and falls around 1m everyday
Nicely done! Would love to see more about flow measurement devices like Parshall Flume
5:55. Minnesota represent!
At 01:15 what dam is that? Never seen it before and I love dams.
studinthemaking Right?! That's pretty gnarly looking.
Hey! You're a ginger! New lights? Never noticed before...(great schtuff btw)
Your videos seem to end a demo or so early.. It leaves them feeling unfinished..
Nice introduction, coverage of the subject, demonstrations of the problems and effects, explanation of the solutions.. Then no demo of a 'proper' jump in your model, just a shot of the 'natural' transition point again, without the structure designed to create the jump..
It's frustrating as your videos are /so/ interesting but they just seem to end on a bit of a cliffhanger.
This is an amazing video describing the phenomenon of HJ. I really appreciate ur work.
Helluva tie-in for that native advertisement. I'm not hating on it at all...that's awesome.
I know, I know, it's a misspelled Hydraulic P- ump
I would welcome a piece about Robert Manning and the development of the Manning Equation.
3:13 please do!
Great video! I'm a CFD engineer and still found it fascinating.
Joshua Dees - 2019-04-20
Me: It's 2 AM, I should go to bed.
Youtube algorithm: What is a hydraulic jump?
Me: Excellent point
TheLegokid - 2020-06-29
True
Nero Erudite - 2020-06-29
I can feel you
Tobias van den Berg - 2020-07-13
@GOAT thats always the most fked up moment xD
Chon Connor - 2020-08-19
engineered dirt raises his hand
Dave - 2020-08-24
I’ll have you know it is only 1:34am.