The Physics of Windmill Design

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3 жыл бұрын

This video was created in partnership with Bill Gates, inspired by his new book “How to Avoid a Climate Disaster.” Find out more here: gatesnot.es/3u7UUVU
This video is about how physics dictates the design of modern windmills - why they are so big, have so few blades, and have such skinny blades.
REFERENCES
H. Glauert: Aerodynamic Theory, 1935 Division L (Airplane Propellers), Chapter XI: Windmills and Fans
Wind power extraction fundamentals
home.uni-leipzig.de/energy/en...
Betz's Law
en.wikipedia.org/wiki/Betz%27...
Tip Speed Ratio
en.wikipedia.org/wiki/Tip-spe...
Aerodynamics of Wind Turbines Book
www.amazon.com/Aerodynamics-W...
Penn State Wind Turbine Aerodynamics Lesson
www.e-education.psu.edu/aersp...
Wind Power Physics youtube video
• Wind Power Physics
Why do Wind Turbines Have Three Blades?
/ why-do-wind-turbines-u...
Wind Power Fundamentals
web.mit.edu/windenergy/windwee...
Wind Power Explained
www.calcunation.com/blogs.php...
Drag Coefficient
dx.doi.org/10.1615/AtoZ.d.drag...
Reynolds Number and Drag
www2.eng.cam.ac.uk/~mpj1001/le...
Reynolds Number
en.wikipedia.org/wiki/Reynold...
Viscosity of Air
en.wikipedia.org/wiki/Viscosi...
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Link to Patreon Supporters: www.minutephysics.com/supporters/
MinutePhysics is on twitter - @minutephysics
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Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry Reich

Пікірлер: 2 000

@Squantle 3 жыл бұрын

I’m scared for that bass player, forever trapped in the recording studio playing the same riff.

@stevenutter3614 3 жыл бұрын

I'm scared for your fingers, forever trapped in your mom's basement typing the same comment.

@Synthetica9 3 жыл бұрын

I fear not the bass player who has practiced 10,000 riffs once, but I fear the bass player who has practiced one riff 10,000 times.

@joeyhardin5903 3 жыл бұрын

@@stevenutter3614 im bouta end this mans whole career

@Squantle 3 жыл бұрын

@@stevenutter3614 bad day?

@DC-cx9ye 3 жыл бұрын

These chats are getting wholesome now

@JohnSmith-kj2od 3 жыл бұрын

I'm not gonna lie, This hasn't ever occured to me and don't think it would ever have without this video

@Kapin05 3 жыл бұрын

@@dontreadprofile1834 OK

@drGigg 3 жыл бұрын

You lie a lot?

@mattmarzula 3 жыл бұрын

Are you working or do you plan on working in an engineer field dealing with the construction of wind turbines? Because unless you are, this information is superfluous. Additionally, if you are planning to join that field, this concept didn't occur to you, and you're over the age of 12... Cash your chips in kid. You're only losing at this game.

@sponge1234ify 3 жыл бұрын

@@mattmarzula but what if he wants to know because... he's just curious? Can't a man question their world, no matter how irrelevant it is in their path of life?

@michaelduffy3866 3 жыл бұрын

@@sponge1234ify Amen

@jorndielen1568 3 жыл бұрын

Fun fact: now a days a lot of wind mills come with serrations. Which are tinny triangle like shapes put in rows on the back side of the blade to reduce the noise the blade creates from cutting true the wind. The idea is based of the wings of an owl. I work as a techician on these things so further questions are welcome :)

@KanishkaWijesekara 3 жыл бұрын

In Texas we saw windmills freeze a few weeks ago. Was it the electrical equipment inside the hub that malfunctioned or did the spokes just stopped spinning after freezing? How can windmills be freeze proofed in future?

@tylerdurden3722 3 жыл бұрын

Aircraft wings damage signicantly faster when flying low. In my mind, wind turbine blades are like aircraft wings flying very low, 24/7. What witchcraft goes into those blades to make them withstand that kind of abuse?

@jorndielen1568 3 жыл бұрын

@@KanishkaWijesekara normally temperatures like that don't occure there so the turbines build are, let's say, "normal" models. Usually when turbines are build in areas where such low temperatures are present they use "Cold climate" types. They have heating everywhere (including in the blades), use special metal alloys that can withstand temperatures up to - 40°C and special grease types as wel.

@RhodokTribesman 3 жыл бұрын

@@KanishkaWijesekara A ton of places winterproof their wind turbines (turbines are used in arctic research bases). Texas' energy problem was NOT wind's fault lmao, gas lines froze and so did turbines; Texas did not listen to suggestions after 2011 and so the non-winterized energy grid was cripples

@jorndielen1568 3 жыл бұрын

@@tylerdurden3722 I don't know for aircraft but wind turbine blades are usually made to be very resiliant. Especially for bending since the force on the "wings" are spread over a bigger surface. I don't know for other companies, but at ours the blades are made by taking glass Fibre mats in a mold and vacuum impregnation them with resin to make them strong but still very bendable.

@flupoop 3 жыл бұрын

I have a master's in energy engineering but the fact about the rotation speed was new to me. You never run out of learning. Thanks.

@phantomhck 3 жыл бұрын

300 ft turbines have larger blades, 400ft turbines have smaller. It depends how close to water they are. The upper third is the main wind generator but puts an enormous stress on the supporting tower.

@pablogriswold421 3 жыл бұрын

Another way to think of it without the ball and sliding wedge analogy is just that faster wind has a higher reynolds number as it passes over the blades, meaning that its inertia is comparatively more dominant over the viscous forces. Very inertial flow wouldn't pick up any rotation, and minimizing the viscous effect also reduces loss. One last thing is that, considering the blades to be airfoils, they have a coefficient of lift and coefficient of drag in the radial direction, the ratio of which determines the steady-state angle of attack. With low Cd, you get a low angle of attack, which means that the turbine has to spin quickly at a given wind speed to be in equilibrium. So low-drag, high-efficiency turbines are designed to spin fast!

@utetopia1620 3 жыл бұрын

This is something you learn only when you do a PhD in energy engineering

@IFearlessINinja 3 жыл бұрын

It's just a fancy way to show the work done on air, so it feels like something I should have seen before too. I like the explanation a lot!

@rosepinkskyblue 3 жыл бұрын

Maybe this is why they made fun of Howard No offence I’m just building on the phd joke

@filippoorologio6777 3 жыл бұрын

watched these guys since middle school, and they haven't changed much.

@l1mbo69 3 жыл бұрын

Except that they upload a lot less now

@SantoLucasST 3 жыл бұрын

Seems like you're getting younger, that or you went to high school when you were 4 or something

@aresorum 3 жыл бұрын

I watched these guys when I was an adult, and I still am, thus I may or may not have watched them for a long time.

@gaeb-hd4lf 3 жыл бұрын

guys?

@familyguydominicdiesel4839 3 жыл бұрын

There is only ONE guy

@EEVblog 3 жыл бұрын

In theory and simulations there are designs that use ducting around the blades and other mechanisms that claim to have beat Betz's Law. But in practice none of them have worked. Many wind turbine startups have tried and wasted a lot of investor dollars. Commercial wind turbines usually cap out at around 80% of Betz's law due to the hubs and other design factors.

@SovereignStatesman 3 жыл бұрын

That's because they're focused on mechanical efficiency, and not ECONOMIC.

@Terra_Lopez 3 жыл бұрын

Interesting, thanks!

@Rotaretilbo 3 жыл бұрын

@@jimbob1353 I guess it would be more accurate to say that they focused on the pursuit of greater mechanical efficiency to the exclusion of considering economic efficiency. Rather than settling for a suitably efficient design that already exists, they continued pouring money into reaching for an even more mechanically efficient design that ultimately proved out of reach. Not to say that is a bad thing. That's basically how innovation works: pursuit of of new, better things that might not turn out, even if it is more immediately and securely profitable to settle for existing designs.

@DarkJokingDragonSP 3 жыл бұрын

@@jimbob1353 Let's say you have a design that is 100% efficient, with a core build out of gold that need replacement every three months. Let's say the alternative is made from steel and aluminium, is 75% efficient and needs replacement every two years. Three mills of the first design provide as much energy as four of the second design. In the first option you need to replace replace a core on average every month, while in the second case every six months. Ignoring the fact that gold is way more expensive compared to steel/aluminium, it would still be six times more expensive to go for three of the first design compared to four of the second.

@bronzedivision 3 жыл бұрын

@EEVblog I do wish you'd actually apply the baloney detection kit, rather then get swept away by the marketing hype. Fact is, everything that's true about the small energy schemes you debunk is also true of renewable energy in general. Just on a bigger more traumatic scale. It's the modern day alchemy, a hopeless idea that has no hope of fruition. That's why the only future for energy is nuclear power, the only thing we're 'debating' on this issue is how much everyone suffers before doing what was always the one scientifically valid option anyway.

@physicsfun 3 жыл бұрын

I love a video that answers questions I only know I had as I watch the video- noticing lately smaller turbines along the highway being replaced by larger ones.

@Freakwave26 3 жыл бұрын

That is why I love this channel. There are always these little things in life where I ask myself "why is it that way" or "how does it work" but the thought doesn't stick long enough to actually do some research. And then a video like this pops up and enlightens me on one of those things i've always wondered about.

@trumanhw Жыл бұрын

WINDMILLS .... make sense..?? Even though NUCLEAR exists..? We'll just use the energy from reeaaaallly really far nuclear reactions at 513 light seconds away ... ey? Hmmmk.

@theboulder942 3 жыл бұрын

I read it as "Why don't windmills have snails" at first and I was granted a glimpse into a much brighter timeline

@mattwhaley1865 3 жыл бұрын

One where you aren't beat by a blind girl?

@Rosa-cr7qc 3 жыл бұрын

@@mattwhaley1865 bad day?

@mattwhaley1865 3 жыл бұрын

@@Rosa-cr7qc have you never watched avatar the last airbender?

@isaach1447 3 жыл бұрын

Not to mention the shear force being applied to the tower. If you replaced the blades with sails, The tower would have to be massive to support the horizontal force being applied to the nacelle.🌬

@MrBlaBlaCook 3 жыл бұрын

Isnt the force equal to energy made? From the video it seemed to me as if the force is still the same (or even bigger with small, fast turning blades). Is it? The sails would be also turning and letting wind through.

@isaach1447 3 жыл бұрын

@@MrBlaBlaCook you would still have to limit the speed of the sails due to centripetal forces. Therefore you would be relying on the sails to push harder, not faster, and then take advantage of the additional force through internal gearing.

@TimurIskhodzhanov 3 жыл бұрын

@@MrBlaBlaCook No. In the extreme example of big sales that stop the wind entirely, the energy made will be zero while force applied will be high. Power = Force x Velocity.

@ImKibitz 3 жыл бұрын

Never thought about this, cool video!

@trustedjoy4960 3 жыл бұрын

woah didn't expect your comment to be the first i see

@deveshsingh4214 3 жыл бұрын

Kibitz learning this for Satisfactory and Dyson sphere.

@trustedjoy4960 3 жыл бұрын

@@deveshsingh4214 Ye lol

@anirbanchatterjee4794 3 жыл бұрын

Hi, I'm Kibitz, and welcome to Satisfactory. Today we learn about windmills. Goes on to create 100 bejileon watts of nuclear power.

@tunatutuncu2221 3 жыл бұрын

Hey Kibz!

@saali6860 3 жыл бұрын

“What kind of music do you like?” “I’m a huge metal fan”

@LuaanTi 3 жыл бұрын

Actually, not made out of metal :P

@saali6860 3 жыл бұрын

What is? Metal? Of course not it's a genre of music...

@yeyo101 3 жыл бұрын

Teacher: there are no stupid questions Student: why don’t windmills have sails? Teacher : bill please don’t ask stupid questions

@MotoCat91 3 жыл бұрын

I'd love to see a follow up to this comparing the 3 bladed direction windmill to those smaller profile helical ones which work in all directions

@dlahouss 3 жыл бұрын

Don't the 3-blade ones turn, thus working in "all directions"?

@TimLF 3 жыл бұрын

There are major difficulties in protecting the Darrieus turbine from extreme wind conditions and in making it self-starting. en.wikipedia.org/wiki/Darrieus_wind_turbine

@groundzero_-lm4md 3 жыл бұрын

Don't those helical ones work less well due to the blades needing to fight the wind on their way back? The 3 bladed ones can also turn like the turret of a tank, letting them adapt to wind direction.

@HJSDGCE 3 жыл бұрын

I actually did some research about this. Long story short; helical wind turbines aren't that efficient. It has a slower rotational speed, thus producing less power per square meter. It does come with advantages however such as being able to work at any direction of wind without needing to turn, taking up less space and have a lower minimum wind speed to work.

@SovereignStatesman 3 жыл бұрын

Motocat: Yeah at about 3% efficiency. There's no problem with putting a turbine on a rotating shaft; just mount the turbine on a tire-rim and axle from a junk car, and mount the generator on the front as a counterweight.

@Canadian_Ry 3 жыл бұрын

Isn't it supposed to be a 'wind turbine' as opposed to a wind mill? I suppose 'rotating bladed wind energy capture device' isn't very relatable.

@DavidGuild 3 жыл бұрын

No it's a wind mill. By law, anything that captures wind must have a tiny millstone and a supply of grain to grind. (This is a joke.)

@craigwall9536 3 жыл бұрын

Consistency is the hobgoblin of small minds.

@zarehs 3 жыл бұрын

@@craigwall9536 In general yeah! But in this case - its an educational video needs be correct. Fortunately its mentionrd in this comment section

@hedgehog3180 3 жыл бұрын

In Denmark they're called wind mills and I feel like we have the final word in this.

@Lefers94 3 жыл бұрын

@@hedgehog3180 do you? As a german, i would relegate all windmill related duties to the dutch. But maybe im wrong.

@MordecaiV 3 жыл бұрын

I appreciate that you have to vastly simplify to get these across in a short time, but another design element that affects the design is the designed wind speed range. Lower cut-in and lower operating wind favors a higher blade count. This is why 'old west' homestead water pump windmills are multi-bladed with a 'solidity' of around 60-80%. They are optimized not for peak power, but low speed wind operation and better torque. Source: Graduate Level Wind power design course at the Technion in Haifa, Israel.

@schipe 3 жыл бұрын

Old west windmills also didn't have cfd optimized design. The low ar makes me curious, why was it ideal? Maybe just for durability and easier rotation to wind angle?

@MordecaiV 3 жыл бұрын

@@schipe I assume you mean low disk area by ar. I think the main thing keeping them smallish was a combination of cost, weight, and being only large enough to suit the purpose of moderate power needs (pumping a well) vs general purpose power generation. Larger would not only cost more, but in most cases would only result in wasted water. Also, keeping the solidity high while minimizing the starting inertia (both helpful for low cut-in speeds and intermittent wind) helps drive you toward smaller designs.

@schipe 3 жыл бұрын

@@MordecaiV Sorry, i meant aspect ratio. For the same force, you can use longer narrower blades. I think as you mentioned, it most definitely comes down to structural strength, longevity. The larger the radius, the more stress you put on the disc and the bearings.

@ChadEichhorn 3 жыл бұрын

As homework in my Computational Fluid Dynamics class, we had to determine what percentage of the wind's energy was extracted by a provided modern windmill design as we altered the number of blades. Everyone thought their results were wrong - 3 bladed windmills were notably less efficient than 4 bladed ones, which were a tiny bit less efficient than 5 bladed ones (efficiency started falling past 5 blades). If our results were correct, why did we only use 3 bladed windmills in practice? The answer, our professor explained, was cost-benefit analysis. Sure you could get more energy out of a 4 or 5 bladed windmill, but the blades cost a lot of money. Someone determined that for the lifetime of a windmill, the cost of the 4th blade wasn't recovered by the additional energy gained, and so we only see 3 bladed ones.

@nachtegaelw5389 2 жыл бұрын

Do you know how long modern blades tend to last? Just curious! They seem like they’d be hard to replace since the towers are so tall! Also, do you know how they figure out how to space windmills when a bunch are in the same area?

@w0ttheh3ll 4 ай бұрын

@@nachtegaelw5389 the blades typically last as long as the rest of the installation, 20 to 30 years. if a blade needs to be replaced (e.g. due to unexpectedly high abrasion at the leading edge, failure of lightning protection or manufacturing defects) that's a major economic setback. Blades are inspected regularly by climbers or helis and can also receive (limited) maintenance.

@MindLaboratory 3 жыл бұрын

Also, just basic engineering - the less material you can use to get the job done, the better. These blades are already enormous, difficult to move around, extremely heavy, and expensive.

@romaindubray2325 3 жыл бұрын

That is a terrible rule of thumb for anything that is built to last. Building more robust might mean higher upfront costs, but could also mean lower maintenance and risk of failure down the line.

@jonathanodude6660 3 жыл бұрын

@@romaindubray2325 ? there has been no issues with the longevity of windmills. their "difficult to move around" status and the fact that theyre designed to work in heavy wind means that they arent going to have many issues short of a natural disaster or coordinated effort to destroy them.

@romaindubray2325 3 жыл бұрын

@@jonathanodude6660 Didn't you just agree with me ?

@jonathanodude6660 3 жыл бұрын

@@romaindubray2325 you said building with less material is a terrible rule of thumb. i said that even though windmills were designed like that, it hasnt caused the issues you mentioned. also its good for reducing waste.

@GeoffCostanza 3 жыл бұрын

@@jonathanodude6660 windmills only last 20 years, and are extremely difficult and energy intensive to recycle, so they are quickly filling up landfills

@PaulPaulPaulson 3 жыл бұрын

Beware: After watching this video, you might get spam mails with subject "enlarge your windmill"

@Mike__B 3 жыл бұрын

As long as it's all natural I'm fine with it

@sponge1234ify 3 жыл бұрын

@@Mike__B where may i find this coveted All-natural Windmill?

@KangJangkrik 3 жыл бұрын

Yeah confirmed exist, but with different subject. More like "Windmill installation discount"

@jliller 3 жыл бұрын

"After watching this video, you might get spam mails with subject 'enlarge your windmill'" That would blow.

@schmidt403 3 жыл бұрын

Last semester I had a month-long freshman engineering project where we investigated all kinds of aspects of windmill design. My team struggled to understand some of the results of our measurements, and this video was a major epiphany moment for me. For instance, we found that power generation didn't necessarily scale with blade count - a medium number of blades generated the most power, and also allowed for a faster windspeed through them. We figured this had something to do with turbulence, but this video really put it all together for me. I wish I had seen this last semester!

@TheScienceBiome 3 жыл бұрын

Its always hype when Minutephysics uploads

@ldt336 3 жыл бұрын

Sorry to be so pedantic but it's more accurate to call modern 'windmills' wind turbines. The term windmill came from when they used the wind to drive a grain mill for making flour. Turbines extract energy from a fluid, typically to produce power. Hence, wind turbine. :)

@tastethejace 3 жыл бұрын

Good point

@peterlinfield 3 жыл бұрын

I always thought the windmill term was used by people trying to ridicule wind turbines by making them sound old fashioned or something. I never realized that people use them interchangeable. Turbine is correct. :)

@TheGag1000 3 жыл бұрын

Or be more german and call it a Windkraftanlage.

@thesteaksaignant 3 жыл бұрын

Or be french and call the éoliennes (= eolians) I don't know why but I find this name very classy, sounds like something out of a fantasy novel

@silversjohn7363 3 жыл бұрын

in croation it's called a "wind power plant"

@JAzzWoods-ik4vv 3 жыл бұрын

Bass riff is in 5/4 and this is the first time I’ve seen someone talk about in the comments. Interesting

@jobta 3 жыл бұрын

As a wind turbine design engineer, I understand why you call them windmills even though they are wind turbines, but it still bothers me a bit ;) Regarding size and speed, in practice and as a general rule, the bigger the rotor the slower it spins. Even though wind turbines are designed to maximise power they also have to follow strict rules such as noise limits. If you imagine 2 wind turbines, one big and one small, spinning at the same angular velocity, the tip speed of the bigger blade is going way faster that the small one. This can make a lot of noise and if you account that it ca also get in the range of supersonic speeds then a lot of other problems might come (ex: aerodynamics change, more vibrations inducing fatigue and lower component life etc). Great video as usual :)

@TheRDBat5 3 жыл бұрын

Notice how at 0:09 he just refuses to include nuclear energy when suggesting clean energy sources

@ThisNameIsBanned 3 жыл бұрын

Its paid by Gates, its partially propaganda for the book and agenda. Doesnt mean its bad, but it has quite some bias.

@TheOwenMajor 3 жыл бұрын

Notice how it's Bill Gates new world propaganda? This guy's always been a lefty, it's not about science, it's about control.

@stickmanonastick6089 3 жыл бұрын

Nuclear energy is cleaner than other energy sources, like fossil fuel, but not entirely clean like wind, water, and sun power, as there is still some nuclear waste to deal with. Thus, it’s a good stepping stone on the way to completely renewable energy, but not a permanent solution.

@mattg8116 3 жыл бұрын

@@stickmanonastick6089 There is no such thing as perfectly renewable energy. Everything creates waste to some degree. Nuclear has been proven comparable if not better than wind and solar in this regard. That said, wind and solar (especially solar) should be developed as much as possible where it makes sense geographically.

@TheOwenMajor 3 жыл бұрын

@@stickmanonastick6089 The idea that wind and solar is clean is ridiculous. It's a classic example of activists playing accounting games to justify there narrative. Wind and solar are horrendously polluting when you factor in their manufacture and after life waste. And that waste is large because wind and solar have significantly shorter infrastructure lifespans then other forms of production.

@shashwatpandey1371 3 жыл бұрын

I loved that block & ball illustration, very accurately captures the reason for specific shape of the blade! 💯

@rfldss89 3 жыл бұрын

Wait, but pelton turbines are most efficient when they capture all the kinetic energy of the fluid, why isn't it the same for wind mills?

@feryth 3 жыл бұрын

The fluid gets out of the way due to gravity, air can't do that

@eolyas1664 3 жыл бұрын

Because water will move out of the way of the newly incoming water thanks to gravity. Air doesn't. At first, wind will flow, but most of it will be stopped by the windmill, creating an area of still wind. This makes the incoming wind stop, not on the windmill, but on the air that stopped earlier. It is for the same reason parachutes need a hole at the top, to allow the air to flow through it.

@seraphina985 3 жыл бұрын

@@eolyas1664 More simply it's the fact that when designing the system you don't release all of the potential energy of the water before using it to drive the turbine. You leave it with enough that releasing it is sufficient to do the work of accelerating the water out of the turbine hall and discharge it from the outlet. So you are still not really capturing its maximum potential but it's more efficient than the alternative which would require some other means to remove the energy-depleted water and discharge it. Trying to pump it out would be an inefficient potential>kinetic>electrical>kinetic conversion when you can just skip the last two and their associated losses if you simply save a fraction of the potential energy to release after the extraction process.

@AlRoderick 3 жыл бұрын

The fact that there's a downstream drain that lets the water flow away proves that it didn't gather all of the *potential* energy from the water. If it had, that would imply that the turbine was sitting in the reservoir at the bottom of the dam, and would therefore fill up with water and not be able to move anymore.

@drawapretzel6003 3 жыл бұрын

because real wind isnt compressed and shot out of a noozle.

@ozonekidd 3 жыл бұрын

Excellent use of simple animation to impart complex physical science to a reasonably intelligent lay person.

@davidequattrocchi5083 3 жыл бұрын

Finally an explanation that made sense, and answered a question I had in my head for nearly a decade. Thank you

@sundroid7562 3 жыл бұрын

Love it! Thanks for answering a question that I've always had in the back of my mind

@whollypotatoes 3 жыл бұрын

This was a beautifully concise video. Well done.

@jplmedley 3 жыл бұрын

so satisfying to have something I never really thought about broken down so succinctly.

@mohammedjakhirhussain8699 3 жыл бұрын

Where's the smart guy who explain complex videos like these in a single line with *BOLD* letters?

@user-po2bo9hi8u 3 жыл бұрын

At last, something interesting that I did not even notice in normal life and not too complicated to become boring. A perfect minutephysics video

@Rock4everNRoll 3 жыл бұрын

Other KZfaqrs: This video brought to you by Raid Shadowlegends... Minutephysics: This video was created in partnership with BILL GATES

@ancap_rem 3 жыл бұрын

I prefer the former.

@zebyurd9530 3 жыл бұрын

@@ancap_rem Wtf is wrong with you

@ancap_rem 3 жыл бұрын

@@zebyurd9530 I don't support someone who hangs out with pedophiles and supports China's genocidal campaign and wants global authoritarianism.

@zebyurd9530 3 жыл бұрын

@@ancap_rem What the heck kind of propaganda have you been reading? Let me guess, you’re a huge trump supporter and probably believe that the election was faked.

@martin_hansen 3 жыл бұрын

Seen many articles and vids on this topic. This time i finally got it. Great explaining skills. Thanks.

@jto9866 3 жыл бұрын

this was the most interesting video i've ever seen concerning windmills, incredible job :D

@Dr.eminence 3 жыл бұрын

I love your animation skills :)

@drumna 3 жыл бұрын

who doesnt :)

@ubgqv 3 жыл бұрын

@@drumna Any idea what app is used to make the animations?

@SiMeGamer 3 жыл бұрын

@@ubgqv no app. It's drawn by hand (at least they used to). There's a behind the scenes video on the matter from a few years back. If they moved to digital then they could technically just have finished drawings and use masking in any video software to reveal them and it creates the illusion of drawing.

@ubgqv 3 жыл бұрын

@@SiMeGamer thank you

@DyslexicMitochondria 3 жыл бұрын

I asked a windmill what kind of music it liked It replied "I'm a big metal fan" Edit : I make videos on science too :)

@mattearenzi8972 3 жыл бұрын

cool channel man

@danielretardo7075 3 жыл бұрын

And I am a big fan of your videos

@moremitochondria2737 3 жыл бұрын

xddd

@damncat2793 3 жыл бұрын

Cool pfo

@Hewhoroamstheinternet 3 жыл бұрын

JAJAJAJJAJAJ

@konradfischer9462 3 жыл бұрын

Summaries in the end are awesome. Love your videos!

@commieSlayer69 3 жыл бұрын

Another factor: More blades makes the structure heavy and shifts the CoG of the structure upwards which makes it less stable and increases construction cost

@Sailorski75 3 жыл бұрын

The fastest sailboats hardly even use sails anymore, they’ve largely switched to wings.(they also don’t float during racing). Check out the America’s Cup

@strcmdrbookwyrm 3 жыл бұрын

Technically, in certain configurations, a sail is functioning as a wing (mainly when going upwind).

@katherinelima7432 3 жыл бұрын

Shame that you never discussed the reason for having odd numbered blades too! I always found it fascinating. If I remember correctly, it had to do with maintenance and stress on the blades due to asymmetrical air resistance.

@joshmusic9766 3 жыл бұрын

it is a shame but its hard to fit it all in. Interestingly enough, 1 blade would theoretically be the most efficient, but could never happen due to the intense forces of wobbling back and fourth. Two blades would have a similar issue with intense forces but from gyroscopic procession. Four blades would not be efficient due to what was mentioned in the video as stopping the air and not allowing enough to pass.

@hookerno 3 жыл бұрын

It is so because of the "tower shadow". If there were paired number of blades, the uppermost one would experience the most torque due to the faster air speed. The lowermost one is aligned with the tower and has low torque due to the effect of the tower to the airflow. This situation where unbalanced torques are present is bad for the mechanical strength of the nacelle. With odd number of blades the "tower shadow" effect is minimized.

@stelioslaz7556 3 жыл бұрын

These videos are important for the understanding of the possible solutions. Keep making 👌 they help.

@sudhakarankarunakaran6932 3 жыл бұрын

Wonderful narration of fluid dynamics. 👍

@hacked2123 3 жыл бұрын

I wanna see a city that uses windmills on the end of it, and buildings along the way channel the wind to a focused path.

@SwedeOnRoad 3 жыл бұрын

Wind turbines isn't efficient as a power source

@vitasartemiev 3 жыл бұрын

Man, the falling ball and slanted block thing took me way to much time to figure out

@ricoautosauve7849 3 жыл бұрын

Care to explain

@joshmusic9766 3 жыл бұрын

@@ricoautosauve7849 Like throwing a baseball off the back of a moving car versus off the back of a stationary car.

@enderyu 3 жыл бұрын

@@ricoautosauve7849 Work done on the object = Change in kinetic energy = Force x Distance traveled During the collision, the forces on both objects are the same, but with the slope moving in the direction of the force, the energy stored in the compression from the elastic collision is more quickly depleted, leaving very little time for the ball to accelerate back and regain speed. With the moving slope, the change (Δ) in speed and momentum are smaller for both objects, but the increase in kinetic energy of the slope is higher since it increases quadratically with speed

@davidadams421 3 жыл бұрын

I never knew that I needed to know this until you let me know of my need. Great video.

@MrUtak 3 жыл бұрын

I keep imagining weird sail/blade shapes with randomly allotted wholes in them so that they don’t resonate in any particular frequency (after reading Humble Pi), great video!

@dante224real1 3 жыл бұрын

"when shit hits the fan is you still a fan?" -Spindrik Llamarks

@pancake_boi9891 3 жыл бұрын

Me: It is impossible to get sponsored by Bill Ga- Minutephysics : 3:07

@tylerdurden3722 3 жыл бұрын

He's been sponsoring a lot of yt channels lately. Accompanied by the types of products his companies sell.

@TheTubejunky 3 жыл бұрын

@@tylerdurden3722 I notice this too. It's not an agenda thing is it?¿ Probably... History repeats itself.

@tylerdurden3722 3 жыл бұрын

@@TheTubejunky he's a businessan. Nothing wrong with that.

@TheTubejunky 3 жыл бұрын

@@tylerdurden3722 Yup nothing wrong with "Business as usual" , I'm sure his goal in the end is innocent and not about power or control. Google is also a business but they only want you to conform to their agenda also.

@Vastin 3 жыл бұрын

Nice work, that was solidly informative. Thanks!

@coolbro8922 3 жыл бұрын

You are descriptive, but also fast. I like this channel for rushing evasions

@Umski 3 жыл бұрын

Windmills DO have sails (or sweeps as they're known in the South East of the UK!) at least ones that actually 'mill' - wind turbines on the other hand have blades ;)

@carazy123_ 3 жыл бұрын

I’ve always wondered about this. Thank you!

@leoingson 3 жыл бұрын

Same here.

@Drag0nStorm1 3 жыл бұрын

Amazing. Thanks for the well done explanations!

@NicholasKratzer 3 жыл бұрын

Thank you for making this. I've low key wondered this for years.

@BEdwardStover 3 жыл бұрын

Hmm, do mean wind turbines? You know wind mills mill grain.

@WadcaWymiaru 3 жыл бұрын

Here is HOW to spell it: *BORD CHOPPERS* good! Repeat!

@AJ-xc8tz 3 жыл бұрын

this is such a good concise video! thank you well done!

@nineball039 3 жыл бұрын

Thank you. I never thought about the physics of windmill design.

@cardinal3728 3 жыл бұрын

Amazing!

@lazyman7505 3 жыл бұрын

Re the energy imparted on the wind by the blades - would adding the 2nd wind turbine with reversed blades right after the 1st help in this case? Similar to how multi-rotor helicopters work.

@ResandOuies 3 жыл бұрын

It might cancel out the twisting of the wind stream, but it's not the fact that the wind is twisting that's the issue, it's the work done to make it so. Adding more work into the system to stop the twisting shouldn't help, I'd think. Multi-rotor helicopters cancel out the twisting of the helicopter, where it's mainly the twisting it self that's the issue, not the lost efficiency

@tylerdurden3722 3 жыл бұрын

Twisting wind behind the rotor blades equate to inefficiencies. Adding another rotor, behind the first, won't make the first rotor more efficient 🤷 And the idea is to extract the maximum energy out of the wind, with minimal material used.

@kilianschabort6347 3 жыл бұрын

I agree with the other replies but also your setup would only work in 1 wind direction and would prevent the turbines from turning to track the wind.

@kazedcat 3 жыл бұрын

@@ResandOuies Counter rotating fans are more efficient but not as efficient as just making the fan larger. The additional blades is a lot more mass that needs to be supported but it only gives you a small amount of additional efficiency. Adding a duct around the fan also increases efficiency but the mass of the duct makes it not worth it for the additional efficiency they provide.

@arfyness 3 жыл бұрын

You'd be better off just putting the 2nd windmill in the cleanest wind possible. Also, counter rotation would only work if the wind never changed direction, which it is quite famous for doing.

@jpsimas2 3 жыл бұрын

This is the first time I've seen a intuitive explanation of something related do fluid dynamics

@Savvy07 3 жыл бұрын

After watching this video, my fan became windmill.

@nerdlord2411 3 жыл бұрын

Aren't modern windmills called wind turbines since they aren't milling anything?

@laurencefraser 3 жыл бұрын

Technically, in English... Though in casual speech where the distinction isn't relevant the terms are used interchangeably.

@nerdlord2411 3 жыл бұрын

@@laurencefraser So with that logic it is fine to call a windmill a wind turbine, even though a wind turbine doesn't mill anything?

@zeppie_ 3 жыл бұрын

This video tells me that a windmill with a single, extremely long blade would be most optimal

@ronwesilen4536 3 жыл бұрын

And you would be stupidly wrong. Luck us that you are not in charge. He has another video explaining that, so watch it, and think about what you will write before doing so

@ElijsDima 3 жыл бұрын

@@ronwesilen4536 Ron, relax. Not everything in life is a battle.

@amritsingh4251 3 жыл бұрын

There's another video of him explaining why that wouldn't be a good solution

@luciqua2517 3 жыл бұрын

There are such windmills. They use a counterweight on the opposite side of the blade. There are two-bladed winmills aswell. But the threebladed approach is better because the pole the windmill is sitting on blocks the wind. So the one- and twobladed mills can start to oscillate when the force of the wind is interrupted periodically

@ronwesilen4536 3 жыл бұрын

@@ElijsDima oh, shit, i never remember, thanks man, you so cool

@Moonfrog11 3 жыл бұрын

Such a good video Henry

@calvinlee1127 3 жыл бұрын

Finally first ever yt video talk about it

@christophergerety1263 3 жыл бұрын

What’s Bill’s carbon footprint? I.e. does Bill walk it or just talk it.

@SwedeOnRoad 3 жыл бұрын

Probably a lot more than the normal human being. Probably owns oversized buildings, many cars, boats and everything. And does that just because he can not that he must have all of it. My guess is that he doesn't care at all about any of this, just says and does stuff so it sounds good and that he is trying to save the planet.

@ultimatedude5686 3 жыл бұрын

@@SwedeOnRoad He also uses private jets. I think the most important thing is really to get corporations to lower their emissions though

@t1kosuave 3 жыл бұрын

Can you examine horizontal vs vertical wind generstors

@carultch 3 жыл бұрын

Search the terms HAWT wind turbine and VAWT wind turbine, to see some examples.

@andrewb9942 3 жыл бұрын

Love these vids - keep it up!

@ieatnoodls 3 жыл бұрын

This is a great summary and well explained thanks

@bowiebrewster6266 3 жыл бұрын

I don’t fully understand the area part, might need some formulas to get it.

@joshmusic9766 3 жыл бұрын

agreed. Im sure its hard for minutephysics to decide how much or how little detail to include.

@dinodubroja7433 3 жыл бұрын

"This video was created in partnership with Bill Gates" whaaa?

@jonathanodude6660 3 жыл бұрын

you must be new here. he sponsors all kinds of videos at certain times of the year across basically all science channels on youtube. people think he caused covid 19 because his last big speech was "we are unprepared for a pandemic." he was right, less intelligent people dont know how he could have predicted that the glaring holes in american pandemic resistance would lead to a pandemic, and now theyve fuelled conspiracy theories that already existed that hes evil or something.

@crowforcast3583 3 жыл бұрын

@@jonathanodude6660 He did convince oxford not to make their vaccine open source and instead sell it to astrazeneca. He's not innocent khn.org/news/rather-than-give-away-its-covid-vaccine-oxford-makes-a-deal-with-drugmaker/

@Kislay11 3 жыл бұрын

Don't mind me I am here only for the drama that will occur in this comments thread

@SimGunther 3 жыл бұрын

@@crowforcast3583 Using non renewable energy (coal and trees) to power things that are supposed to be "renewable" (electric cars and wind turbines) to accelerate the planet's destruction sounds good to me LOL

@jollihotdog5196 3 жыл бұрын

Oh so that was his purpose after all

@sikhswim 3 жыл бұрын

I’ve been wondering this for a couple decades. Thank you for this video, made it so easy and clear. Yes!!! Next video: jet engines vs props and why they have different fans

@ninjakille316 3 жыл бұрын

I designed wind turbines for 4 years in college and I never realized reducing rotational kinetic energy the wake was part of the reason 3 blade designs are preferred. I always understood it as a just a material optimization. Beautiful video! Hmmm, the reasoning in this video seems to disagree with what is stated on Wikipedia: "Aerodynamic efficiency increases with number of blades but with diminishing return. Increasing the number of blades from one to two yields a six percent increase in aerodynamic efficiency, whereas increasing the blade count from two to three yields only an additional three percent in efficiency. Further increasing the blade count yields minimal improvements in aerodynamic efficiency and sacrifices too much in blade stiffness as the blades become thinner"

@Omnywrench 3 жыл бұрын

Morbo: *WINDMILLS WORK THAT WAY! GOODNIGHT!*

@vinaykumar-en7md 3 жыл бұрын

I didn't think I could ever get to your video so early

@MeisterHaar 3 жыл бұрын

I recently listened to a podcast and they talked about how windmills are super optimized as individual mills but nowadays mills rarely stand alone and are often placed in windparks. It turns out windmills im the past have not been optimized to be used like that and all that is currently done is to optimize the placement of mills in the area. but for example a study they cited found that having some windmills spin the opposite direction could in perfect conditions increase the produced energy of a given area by 40% if I remember correctly. I found that super fascinating and wanted to shared it with you.

@Bendyboy_eso 3 жыл бұрын

Ive thought about this before! Lots of these in my area, so its cool knowing why they look like they do!

@ProPowerMax 3 жыл бұрын

Also the 3 blade design is still a compromise, ideal would be only one Blade but that isn't stable enough

@Your_Paramour 3 жыл бұрын

The structural mechanics probably dictate the design more since increasing the efficiency will have diminishing returns where as the power generation is squared on the blade length and cubed on the wind velocity.

@Uhlbelk 3 жыл бұрын

Material engineering, you need to limit the size and increase the number of blades to reduce the force to any one blade to the tolerance of the materials.

@Keldor314 3 жыл бұрын

This still doesn't explain why a 2 blade design isn't used.

@justinhannan1713 3 жыл бұрын

This single blade turbine seems ok: kzfaq.info/get/bejne/mtabgM5ztZzTp4U.html

@Uhlbelk 3 жыл бұрын

@@justinhannan1713 yes, but that is not the most energy efficient design.

@sammy3212321 3 жыл бұрын

It kinda upsets me that we call turbines "windmills" when they're not even milling anything

@rashidisw 3 жыл бұрын

Yeah, turbines are more appropriate term.

@victortitov1740 3 жыл бұрын

Tin foil, tin can and blackboard have entered the chat!

@victortitov1740 3 жыл бұрын

they mill magnetic fieds to produce electricity!

@KarelKannel 3 жыл бұрын

No, they are milling government support money for owners.

@sammy3212321 3 жыл бұрын

@@KarelKannel It's also kinda gross that so much investment is going into turbines when they have such terrible energy efficiency in convergence :/ They're not helping to give a good name to green energy.

@willjohnson4579 3 жыл бұрын

Im shocked that after all these hours of content you still have more content to make. Been watching this channel for years!

@JoeRose8 3 жыл бұрын

A very concise video in just three minutes

@ajax4887 3 жыл бұрын

I thought they were called wind turbines. A wind mill grinds grain

@Ddub1083 3 жыл бұрын

true but people largely generalize them to wind mills... which doesnt really make much sense because a mill is something that grinds specifically.

@Dayvit78 3 жыл бұрын

Yet here's everyone calling it a windmill. So, who's right?

@Ddub1083 3 жыл бұрын

@@Dayvit78 you can be right but at the risk of being an asshole. I think thats the rule. lol

@BL3446 3 жыл бұрын

Also, lol at all the Dunning-Krugers in the comments. The sources are literally right there for you to read on your own.

@seanforrest1106 3 жыл бұрын

Not gonna lie yo, i dont think this would have ocurred to me if i didnt watch this video. My high school maff teacher called me smart once tho so maybe if i thunk hard enough😅

@BL3446 3 жыл бұрын

@@seanforrest1106 lmao what?

@und3rt3h1nfluence 3 жыл бұрын

This is such! a good explanation! ❤️

@AlexJohnson-be3tj 3 жыл бұрын

Definitely wondered about windmills and their design before

@rupert7565 3 жыл бұрын

And you can find out why windmills have 3 blades from the video of Real Engineering: kzfaq.info/get/bejne/iLSAfLWX3bu4gWg.html

@mementomori5580 3 жыл бұрын

Except that that video has several factual errors and thus should be remade and not shared in its current state.

@rupert7565 3 жыл бұрын

@@mementomori5580 Really? well it's not the only time he made a video with factual errors, see his latest one.

@daniel_960_ 3 жыл бұрын

@@mementomori5580 I mean the dude made a video about how awesome Nikola is 😂 And went totally nuts because he got criticized for it. I liked the channel but can’t trust any his stuff at this point

@An.Individual 3 жыл бұрын

Also they take energy from the grid to get the blades turning so they are never generating as much energy as you might think.

@exactzero 3 жыл бұрын

Is it just me or are anything about aerodynamics is always filled with paradoxes and counter-intuitive solutions? It's amazing.

@DrTune 3 жыл бұрын

I did wonder about this! Thanks

@Aldo_raines 3 жыл бұрын

Anyone else annoyed that they called wind turbines “wind mills”?

@FOVOutdoors 3 жыл бұрын

Me too.

@aidanlevy2841 3 жыл бұрын

The thing a lot of people on the internet seem to forget about language is that when enough people use a word wrong it stops being wrong and simply becomes a new meaning for the word. Do you complain about the wind powered pumps in the Netherlands that pump water out of fields being called windmills?

@lukerab 3 жыл бұрын

Why does a moving block absorb more energy from the ball? I feel like there should be a good explanation, but I cannot think of one for the life of me.

@BL3446 3 жыл бұрын

Not the only reason, but often starting friction is higher than kinetic friction. So it would take more energy from the ball dropping to get started than if it were already going.

@docostler 3 жыл бұрын

The 'reflecting' surface of they block is constantly moving away from the ball, thus lengthening the contact time between ball and surface. This allows more transfer of energy from the ball to the block, thus causing a smaller 'reflection'. The same principle for padded dashboards, air bags, crush zones in cars. Lengthen the contact time by moving with the colliding object to absorb some of the energy.

@brauno3539 3 жыл бұрын

That's a good question. I have an answer, but it is going to get a bit technical, despite a simplification. I'd love to hear more simple answers. Simplification: The ball is very light and doesn't push the block away. If the block is moving, you can change the inertial system to the moving block, and add the speed to the horizontal velocity of the ball (it is like when you are in a moving train, it looks like the landscape is moving by). And that makes it alot easier. With the simplification you can exactly calculate the angles of the incoming ball and the outcoming ball (incoming angle=angle, when it is reflected). Then when you subtract the horizontal velocity at the beginning from the horizontal velocity at the end, you get v(end)=v(start)*[sin(2a+b)-sin(b)] with a: angle of the object b: angle of the incoming ball and v*(end) is smaller, the bigger b gets. and b is dependent from the horizontal speed of the ball

@lukerab 3 жыл бұрын

@@BL3446 That is an interesting idea. But we should expect kinetic friction to be pretty much constant and wouldn't explain the difference between the second and third cases when the block is moving faster.

@lukerab 3 жыл бұрын

@@docostler I was thinking about that as I was watching. I was thinking in terms of impulse, that the extended time would decrease the force on the ball. But I wasn't sure if that was even true and it would also diminish the force on the block due to Newton's 3rd Law. I am still a little confused by the longer time allowing more transfer of energy in terms of equations or laws.