I know that some manual rebreathers are using a valve like this that relies on choked flow to deliver a predictable amount of oxygen (and potentially diluent gas). As long as the pressure ratio is above a critical threshold say 2:1 (depends on the throat area), and the input pressure stays constant at say 10 bar, the mass flow rate also remains the same because the flow is choked, so you could have 10:1 or 100:1 pressure ratio and you'd still get the same amount of oxygen per unit of time, super cool.
Thank you for sharing. This solves a problem that was puzzling me: I once tried to calculate the speed of the gas at the jet of my blowtorch based on how fast the propane tank lasted, the amount of gas inside and the diameter of the jet. I found about Mach 2 and couldn’t believe it could be that fast… I thought I did something wrong, but the math looked right… now I know, it’s indeed supersonic. Thanks again, it deserves a thumbs up and just subscribed 👍
In that case, there might be significant differences from what you calculated because of the temperature change, the fact that air contributes to the mass flow, and the fact that the jet itself is mostly CO2 and steam instead of propane (assuming fairly complete combustion).
@@JonBrase by jet I imagine he's referring to the brass nozzle where the fuel exits at high speed to be mixed with the air. There the jet is propane/butane
@MikrySoft flame arrestor saved him from what? The oxygen and acetylene only mix in the torch head, in a flame is traveling back through the system then it won't be able to go much further than the point where fuel and oxygen takes different paths back to their respective tanks. Also, a normal cutting flame is basically like a continuous detonation. If you turn your knobs to the right settings for a hot cutting flame, but don't light it, and then fill a balloon with that mixture, the balloon will detonate when exposed to a flame. Doing this without hearing protection can seriously damage your ears
I find it under engineered but just enough to prove he's in the right field generally. Over engineered (for the first go, not at the end of the day) would have been very specific about valve openings, tube sizes and lengths between obstructions, temperatures, and backing PSI across time. We'd have a camera on the tank pressure gauge, multiple type and hose sizes, multiple nozzle materials and configurations, room temp gauge, ambient air pressure gauge, and if we're really serious, a gas spectrometer reading of the contents of each canister and the air for reference. We'd be looking to change the temperatures of each item in the chain through the various pressures in each aperture, and, if we're getting really neo-material-science, running ultra high-speed on the tanks, hoses, nozzles, mach diamond paths, and the air around the set-up generally. We might be using high time-cycle digital gauges and plotting charts of flow rates, so that we can draw cross-environment conclusions.
Well I had a burrito from taco bell the other day and boy! It made me exhaust my fluids, I shock diamonds on everything. haha let me know if ya'll think that ones funny?
Super cool, would never have expected to see mach diamonds in simple compressed air sources! Really cool analysis, that schlieren imaging footage is gorgeous
You know its some seriously cool shit when some of the best science/engineering channels start chiming in. Seriously dude, well done. Earned a sub for sure
In compressible aerodynamics we call this increase in velocity of a adiabatic quasi-one dimensional flow in a constant area duct with no heat addition Fanno flow. It is essentially saying that due to boundary layer and viscous effects at the edges, the fluid will accelerate to sonic given any constant area duct is long enough. Meaning with a long enough tube, any pressure above ambient could result in sonic flow. Neat video!
In fact the minimum pressure ratio required to achieve choked(a.k.a. sonic) flow through a restriction is 1/0.528. That means that to get sonic flow from a pressure vessel discharging to the atmosphere the pressure vessel needs to be at above about 2 bar or 29psi, in reality it would be a little more because of pressure losses from friction in the piping. If the pressure ratio increases even more supersonic flow will occur after the restriction but it also depends on the length of piping after the choke
Anyway, after the choke point, you can only get supersonic by careful expansion (you know, rocket bells). Otherwise it will immediately end up in shockwaves. Also, transonic flow in pipes is really complicated topic, the same boundary layer causes a choke point, depending on the length of the pipe.
Thank you for doing this video. I build airrifles for a living and im tired of arguing with people that question my projectile velocities because they think that air is somehow limited to the speed of sound.
To be fair, I don't think most gun people are the sharpest tools in the shed. From my experience, maybe only like 5% actually know what they are talking about.
Weirdly the thin tube is likely why it accelerates so much. In the subsonic regime, steady flow actually accelerates from friction (some weird effect of the heat addition). The model for this process is called Fanno flow. From wikipedia: ‘flow with an upstream Mach number less than 1.0, acceleration occurs and the flow can become choked in a sufficiently long duct.’
@@fietae i actually did the math for the duster and while the tube does accelerate subsonic flow, the pressure difference is enough to choke (go supersonic) in a duster without the tube. The same may be true for the needle, I’m not sure. What psi is a ball inflated to?
@@DJrainbizzles varies by the sport, but anywhere from 1.5 to 2.5 Bar absolute (0.5-1.5 Bar Gauge) (Basketballs are 7.5-8.5 PSIg, Gridiron Balls (American Football) are 12.5-13.5 PSIg, Association Footballs (Soccer to USians) can be anywhere from 9.7-16 PSIg
@@Hyratel 0.5 bar pressure difference can just barely drive supersonic flow (if it lasts), much higher and I could imagine visible shock diamonds showing up. (Math is isentropic flow relationships)
I'm of the opinion getting the shot is more impressive than noticing and documenting the phenomena. I see AppliedScience & BreakingTaps down in the comments. So you're in good company ;-)
Don't forget the videography guys like SmarterEveryDay and The Slo-Mo Guys. With so many big channels from domain experts on a video with ‘only’ 300k views, it's clear that RUclips has suggested it to the _right_ people.
Really cool results! This was basically a junior science project of mine, analysing the supersonic flow speed from these Mach diamonds out of a small air gun with Schlieren photography. For my little overexpanded nozzle at 8 Bar I got around 404m/s (~Mach 1.19) ± 30m/s. Kinda funny that one can do supersonic experiments in their basement with a very minimal setup.
That is neat. I of course, had to immediately grab my canned air and see for my self. It required a little trial and error in getting the right angles, but I was able to reproduce your findings.
Yeah..... being dumb kids we teleported to new worlds with duster..... in reality it just makes u feel retarded similar to N20. Tho n20 "whipits" was a much cleaner safer way to do what we did. We where idiots
Seen that years ago. It only takes 13-14PSI (gauge) in air to choke the flow. In fact if you ever remove the tire valve in an inflated tire , as it deflates you will hear one sound and then suddenly it will change to a new sound. At that change point, if you put a pressure gauge on it it will read 13-14 psi, the sonic threshold. RULE OF THUMB if the exit pressure ABSOLUTE is about 1/2(.5283) or less (or~ 2:1)of the stagnation pressure ABSOLUTE (storage pressure) then the flow is choked @ Mach 1
Honestly, I believe it. It explains why those shits are always SO DAMN LOUD, even just the Staples air cans. When I work in the shop, the compressed air is the thing I always wear ear protection for, more than almost anything else.
Good habit! I'm a metal worker and know plenty of people who will shrug it off as "not needing it" ... they'll be surprised when they try to listen to loud music when they're older. 🫠
This has a great mix of everyday observations, concepts I knew of but couldn't ELI5, jerry rigging/jugaad and pretty images that reminded me what got me into science in the first place. That combined with the numerous big channels by domain experts on a video with ‘only’ 300k views and 9k subs makes it feel like an exclusive club.
I had never heard of shock diamonds and it’s stunning you caught it with your naked eye. Thank you for posting this. I know nothing about your content so I would say don’t assume your viewers know any principle your covering as RUclips recommends people for all sorts of reasons. Great find. I would love it if you want into step by step about setting up the air circulation imaging diy. That was also pretty incredible to me.
Hey there! I just stumbled accross this video... really cool! Never thought about looking shockwaves in compressed air cans in my workshop, though i worked in aerospace and studied shockwaves for years. Simply amazing! You sir are youtube at it´s best!! BTW, really cool precision machining content, SUBSCRIBED!!!
Wow so now I know the feeling of the air chuck when it hits my skin felt like a tiny point is hitting my skin and i imagined it like a cone poking me after a few seconds it starts hurting. It's cool to know I was right about it, I'm still surprised I don't remember or ever made the connection that was it. Thank you I haven't seen anyone show this before. It's amazingly fascinating how the fast moving flow, isn't lamimater flow like I thought. It's actually called "shock diamonds" The same as the supersonic exhaust from a propelling nozzle on a jet fighter. Thanks again for making this video!
Yep. Subscribed. That was awesome and I love your approach to it all. Just step back and deconstruct the issue and you arrived at the solution to observing it how you wanted to. Can’t wait to see more videos. Super interesting.
Definitely one of those things when you think about its obvious, but without supersonic flow and the turbulence it creates I'd bet it would make duster less effective. Actually you can see this as the can gets used up/gets cold. Very neat video, finding interesting topics in everyday things.
Gases flow out of an ideal nozzle slightly faster than the local speed of sound. Intuitively explained now. Speed of sound is the speed at which waves can propogate through a fluid. Temperature is a measure of how fast the individual molecules are bouncing around, ricocheting off each other. The two are the same principle, and in fact temperature rather than pressure affects speed of sound. So, speed of sound is the velocity at which molecules can bounce around and transmit motion from the molecule behind them to the one in front. In the case of supersonic flow, or gas flowing out of an ideal nozzle, there is no barrier of air molecules to bounce off of and transmit motion to, so all molecules end up bouncing around until they get a trajectory that leads them out of the nozzle. All of the molecules are moving in a somewhat laminar flow through the nozzle and out of it. Now, the speed of sound wasnt the measure of how fast the individual molecules were moving due to their temperature, but how quickly they can complete a round trip of recieving and input from behind them and outputing it to the molecule ahead. The speed they are moving is faster than the speed at which they can complete the whole round trip. Once all the molecules are flowing through the nozzle unimpeded, they are theoretically traveling at the speed of their temperature, rather than the speed of a closed loop series of collisions. Because we are witnessing or measuring a one way trip instead of a round trip, the velocity is higher.
I'm an automotive painter and I work with compressed air all day. I see shock diamonds coming from my air blower all the time. I see them best on slightly humid days. I don't know this for a fact but they seem to drop off between 60-80 psi of air in the line.
Was great to see you also included simple compressed air rather than just relying on the denser gas to demonstrate the effect in what I assume is ~1 atm of pressure. Doing so increased the value of this video.
That's really cool work! I've tinkered enough to know that making a setup like this looks easy, but isn't easy. You distilled quite a lot of work into a very coherent and intelligent report. That's awesome, congrats. I learned a lot by watching this.
Very unintuitive discovery indeed! I made a video on this a while back. After talking to some NASA aerospace engineers seems the challenge of supersonic wind tunnels is not getting the gas supersonic, but rather controlling the entropy and temperature of the flow to keep things consistent with flight. Thanks for sharing! Excellent video.
@@dundermifflinity By looking at the stream in front of a light and squinting. I was a curious kid. You don't need a complicated setup to just see it with the naked eye, you just need a complicated setup to record it on video because cameras aren't as sensitive as our eyes.
I've long been aware of high pressure through a small aperture doing this, but I thought it eventually levels out (given no moving parts) and the end hole size mattered (the expanded nozzle example). Neat vid! Thanks for it.
This video just popped up in my feed (I guess the algorithm is working?) and I'm so glad it did! That's fascinating! Who knew that air is coming out of those things so fast! I'm definitely subscribing 😃
I think it is important to point out that the canned air, not actually being air, has a much lower speed of sound. You point out that the speed of sound does change. But these effects are pretty significant at 223K and 5 atm, the speed of sound is easily halved (compared to air at STP). They get even lower if the pressure is greater than 5 atm. There is a really neat article about this published last year [Speed of Sound in Gaseous 1,1-Difluoroethene (R1132a) at Temperatures Between 193 K and 383 K at Pressures up to 3 MPa (Demirdesen 2023)]. Notably, this only applies to the can but I think the lower speeds from the can is kinda intuitive.
As soon as you have more than a factor of ~2 (it is 1/0,528, iirc) in pressure difference at a nozzle, you get supersonic flow. Against atmospheric pressure this means that you only need ~2 bars for supersonic flow. A small laval nozzle can speed it up a little more, but with cold gas you won't get very high in mach numbers.
We do fluid dynamics research and use these gas cans to check our shadowgraph alignment. It's so common to see the diamonds that we think it's mundane. Sometimes we don't realize how good we have it...
I've noticed working with compressed air at high pressures, that I've actually seen some sort of refraction of light, and I thought that is the strangest thing, "How would something like that be possible, it's just air? I should research it" thank you for this video.
this is crazy! but what’s super cool is that this video has brought lots of massive science youtubers to the comments to share their enthusiasm on a small channel! awesome 🙌
Very cool! In a strange coincidence I published a video a week or so ago where my friend demonstrates the Schlieren effect. I'd never heard of it before. BTW, I referred your channel to him and he really likes it.
I hadn’t thought this would be possible until seeing this video, but now I’m absolutely positive that the air released from a semi-truck’s air brakes when the parking brake is engaged also has Mach diamonds in the airflow. The reason I’m sure is because if you’re standing next to the truck when the driver pulls the brake it’s loud enough to cause physical pain within the ears. The sharp hissing sound is at least 130 decibels, if not more.
Have tired reflector schlieren setups but didn't realise refractory lenses can also be used. Looks like you can easily get very high quality schlieren setups like this. Thanks!
Super interesting! I had never even thought of the possibility that air dusters accelerate the gas so fast that it's supersonic. Finding videos and channels like this is my favorite thing about RUclips. The channels Applied Science and The Thought Emporium are also goldmines for stuff like this.
love the title of the video. anti-clickbait, but leaves the question. also super interesting explanations. never really considered that the speed of sound varies based on temperature. mind blowing to a fool like myself
It's kinda crazy that in the US the most common propellants used in canned air are HFCs. In the EU you'll be pressed to find any of that, it's all just propane-butane for the most part. That does make it flammable, so I understand the advantages of HFCs, but in most cases (especially home/hobby usage), I'm not sure they really outweigh the damage they do to the climate.
It's kinda funny actually how the regulations around it are as well. It's highly illegal and you'l get a nasty fine if you intentionally vent even small quantities of HFC refrigerant. But we sell cans of refrigerant you use to dust things off by the thousands of tons. WAT. Sure, it won't put holes into the ozone.... but R-152a, aka Difluoroethane, is around 1200x as potent of a greenhouse gas as CO2 of I remember correctly. It's still mildly flammable as well, and CAN ignite if used in decent quantities near a ignition source. Combustion byproducts are mainly carbonyl fluoride, hydrofluoric acid, and carbon monoxide. One breath of that will leave you with a trip to the ER, from a few reports I read. At least butane would only cause a small fire, there's no way we should be using refrigerant as duster spray. I'd like to have it banned for use as a duster.
A very easy schlieren effect can be seen when sunlight reflects off a convex surface like a car windscreen. I noticed this when my car was parked in just the right spot for the reflection from the windscreen to shine into my workshop through the doorway and project onto the back wall. You will see the best results if you can darken the room by covering any windows etc. The divergent rays of light would show a shadow image which revealed the air currents produced from a blow torch. You could even see the convection current produced from the warmth of your hand if the air temperature was cool enough. To see this you need to place the item being studied about a foot or so from the surface that the image will project onto. This would probably work with a concave mirror as long as you are reflecting the light onto a surface a minimum of twice the focal length of the mirror. The plus to this method is that you have a large area that the image can be seen.
I don't know much but I do know that if you're drinking beer with the neighbor and discover his blow gun and air compressor in the garage, you can put one of those little darts through a tree.
this explains how people are killing sensitive electronics that have fans when trying to dust them. too many people dont realise that if you dont hold the fan from spinning the fan motor will generate electricity. since your blowing air on them at supersonic speeds, its entirely possible that the fans could end up spinning faster then they are designed to and generate more voltage/current then the circuit is designed to handle and then fry components.
That is so cool! I knew that choked flow doesn't require a huge pressure differential, but I never expected shock diamonds like that!
I wonder if there's any papers on this. Might be interesting to see how this can be tweeked for various applications.
Could compressed air be used for nozzle design R&D ? Would this translate well?
I know that some manual rebreathers are using a valve like this that relies on choked flow to deliver a predictable amount of oxygen (and potentially diluent gas). As long as the pressure ratio is above a critical threshold say 2:1 (depends on the throat area), and the input pressure stays constant at say 10 bar, the mass flow rate also remains the same because the flow is choked, so you could have 10:1 or 100:1 pressure ratio and you'd still get the same amount of oxygen per unit of time, super cool.
whoa, it's that guy from that channel i watch
@@alexgustavsson5955 the dudes who understand stuff like this are like wizards.... wtf
Super pretty
you know that you now need to make an expansion nozzle for this, and also build a supersonic wind tunnel for a something small like a matchbox car...
Wow, I really did not expect this amount of reach from this video. Thank you Destin!
Well this is high praise. . .
Collab!!!!!
I was hoping you seen this!
Thank you for sharing. This solves a problem that was puzzling me: I once tried to calculate the speed of the gas at the jet of my blowtorch based on how fast the propane tank lasted, the amount of gas inside and the diameter of the jet. I found about Mach 2 and couldn’t believe it could be that fast… I thought I did something wrong, but the math looked right… now I know, it’s indeed supersonic. Thanks again, it deserves a thumbs up and just subscribed 👍
In that case, there might be significant differences from what you calculated because of the temperature change, the fact that air contributes to the mass flow, and the fact that the jet itself is mostly CO2 and steam instead of propane (assuming fairly complete combustion).
It would explain the "pop" sound you hear when you add too much oxygen in an acetylene torch and the flame goes out. It's likely a Sonic Boom!
@@JonBrase by jet I imagine he's referring to the brass nozzle where the fuel exits at high speed to be mixed with the air. There the jet is propane/butane
@@markc2643 No, that's because you got the acetylene/oxygen ratio to the detonation levels and flame arrester saved you.
@MikrySoft flame arrestor saved him from what? The oxygen and acetylene only mix in the torch head, in a flame is traveling back through the system then it won't be able to go much further than the point where fuel and oxygen takes different paths back to their respective tanks.
Also, a normal cutting flame is basically like a continuous detonation. If you turn your knobs to the right settings for a hot cutting flame, but don't light it, and then fill a balloon with that mixture, the balloon will detonate when exposed to a flame. Doing this without hearing protection can seriously damage your ears
"Aerospace stuff" 10/10 for an over-engineered info video about the supersonic speed of cleaning dusters!!!
I find it under engineered but just enough to prove he's in the right field generally. Over engineered (for the first go, not at the end of the day) would have been very specific about valve openings, tube sizes and lengths between obstructions, temperatures, and backing PSI across time. We'd have a camera on the tank pressure gauge, multiple type and hose sizes, multiple nozzle materials and configurations, room temp gauge, ambient air pressure gauge, and if we're really serious, a gas spectrometer reading of the contents of each canister and the air for reference. We'd be looking to change the temperatures of each item in the chain through the various pressures in each aperture, and, if we're getting really neo-material-science, running ultra high-speed on the tanks, hoses, nozzles, mach diamond paths, and the air around the set-up generally. We might be using high time-cycle digital gauges and plotting charts of flow rates, so that we can draw cross-environment conclusions.
Not “over”. Just right in my view.
"shockwaves coming out of both holes", there is a taco bell joke in there somewhere, but this channel deserves more dignified comments than that...
A number 2 on the menu is every order.
The nozzles quickly changed from under to over expanded. 🎉🎉
This happens when I cough and fart.
imma eat tacobell tonight
Well I had a burrito from taco bell the other day and boy! It made me exhaust my fluids, I shock diamonds on everything.
haha let me know if ya'll think that ones funny?
Really appreciate how non-psychotic and un-grifty this is. No annoying music. A welcome relief.
Super cool, would never have expected to see mach diamonds in simple compressed air sources! Really cool analysis, that schlieren imaging footage is gorgeous
Thanks for your video on ACF tape earlier this year, absolutely lovely stuff.
what a prediction
I am glad the algorithm has shown me this
our algorithms are blessed
This seems like something SmarterEveryDay would be interested in
destin is a dirtbag
Dustin did a whole video about a schlieren imaging. But the pressure here - you’re right that would make a great video.
He just commented
@@banaana1234Lmao
His comment is right above yours lol
I love that this guy just has VS Code running in the task bar, talking about super-sonic air, and making RUclips videos. What a beast!
And McMaster first in the bookmark bar
this dude is the most engineer of all time
As one does. I like seeing that top comment is the one noticing it, kinda speeks to qaulity of this community.
🤯
Woah no way rawr xd rawr
Super slow-mode mach diamonds!? Or better yet, capture some cosmic rays in a thermo-electric cloud chamber. They might be too fast, though. 😅
:3
Hi gav and Dan
cant wait for the video
You know its some seriously cool shit when some of the best science/engineering channels start chiming in. Seriously dude, well done. Earned a sub for sure
My first time on this channel. I noticed that too. Wow!
In compressible aerodynamics we call this increase in velocity of a adiabatic quasi-one dimensional flow in a constant area duct with no heat addition Fanno flow. It is essentially saying that due to boundary layer and viscous effects at the edges, the fluid will accelerate to sonic given any constant area duct is long enough. Meaning with a long enough tube, any pressure above ambient could result in sonic flow. Neat video!
That's really cool
I didn’t learn enough in school to comprehend the fact that people got math for supersonic nozzle flow
It's alright, they didn't teach me rocket science in school either!@@akwinter
Sonic, but not supersonic.
In fact the minimum pressure ratio required to achieve choked(a.k.a. sonic) flow through a restriction is 1/0.528. That means that to get sonic flow from a pressure vessel discharging to the atmosphere the pressure vessel needs to be at above about 2 bar or 29psi, in reality it would be a little more because of pressure losses from friction in the piping. If the pressure ratio increases even more supersonic flow will occur after the restriction but it also depends on the length of piping after the choke
You mean 1:0.528 👍
@@Nate-bd8fg Yes!
Anyway, after the choke point, you can only get supersonic by careful expansion (you know, rocket bells). Otherwise it will immediately end up in shockwaves. Also, transonic flow in pipes is really complicated topic, the same boundary layer causes a choke point, depending on the length of the pipe.
Hey, is that boundary layer choke point like a standing wave ?
@@Grateful.For.Everything well, the shape is similar. The boundary layer thickens along the pipe until the flow is fully chocked.
Finding a radius just right to get clean expansion fans is the hidden gem here
A potential part 2?
I dunno, the mach diamond is where I would believe the most cutting ability arises, and would be of most interest to me.
Thank you for doing this video. I build airrifles for a living and im tired of arguing with people that question my projectile velocities because they think that air is somehow limited to the speed of sound.
Got a link to your air rifles?
@@kylemac8672 Its on my gunsmithing channel. I keep trying to post the name of it and YT is taking it down.
@@JETHO321Can you link the channels so that your channel has a "Channels" tab?
@@prism223 youtube got rid of the channels tab for some godforsaken reason.
To be fair, I don't think most gun people are the sharpest tools in the shed. From my experience, maybe only like 5% actually know what they are talking about.
Weirdly the thin tube is likely why it accelerates so much. In the subsonic regime, steady flow actually accelerates from friction (some weird effect of the heat addition). The model for this process is called Fanno flow.
From wikipedia: ‘flow with an upstream Mach number less than 1.0, acceleration occurs and the flow can become choked in a sufficiently long duct.’
Does that aply to the fottball inflating needle having shockwaves at both holes? 9:53
@@fietae i actually did the math for the duster and while the tube does accelerate subsonic flow, the pressure difference is enough to choke (go supersonic) in a duster without the tube.
The same may be true for the needle, I’m not sure. What psi is a ball inflated to?
@@DJrainbizzles varies by the sport, but anywhere from 1.5 to 2.5 Bar absolute (0.5-1.5 Bar Gauge) (Basketballs are 7.5-8.5 PSIg, Gridiron Balls (American Football) are 12.5-13.5 PSIg, Association Footballs (Soccer to USians) can be anywhere from 9.7-16 PSIg
@@Hyratel 0.5 bar pressure difference can just barely drive supersonic flow (if it lasts), much higher and I could imagine visible shock diamonds showing up. (Math is isentropic flow relationships)
I'm of the opinion getting the shot is more impressive than noticing and documenting the phenomena. I see AppliedScience & BreakingTaps down in the comments. So you're in good company ;-)
Don't forget the videography guys like SmarterEveryDay and The Slo-Mo Guys.
With so many big channels from domain experts on a video with ‘only’ 300k views, it's clear that RUclips has suggested it to the _right_ people.
@@deus_ex_machina_ I care nothing of a bible banger, and clowns that record explosions.
Really cool results!
This was basically a junior science project of mine, analysing the supersonic flow speed from these Mach diamonds out of a small air gun with Schlieren photography.
For my little overexpanded nozzle at 8 Bar I got around 404m/s (~Mach 1.19) ± 30m/s. Kinda funny that one can do supersonic experiments in their basement with a very minimal setup.
It's channels like these that RUclips needs more of!
There are lots of them. The struggle is finding them.
yup and not channels that keep pushing millions of sponsors and bs
Good'ol Ed Schlieren, not just an accomplished musician, but an amazing engineer as well!
Really Cool video, subbed ;)
That is neat. I of course, had to immediately grab my canned air and see for my self. It required a little trial and error in getting the right angles, but I was able to reproduce your findings.
Beautiful imaging. Thank you so much for sharing these! The structure of commonplace pressurized flow is so unexpectedly organized.
That's cooler than my discoveries with air duster
lol
Yeah..... being dumb kids we teleported to new worlds with duster..... in reality it just makes u feel retarded similar to N20. Tho n20 "whipits" was a much cleaner safer way to do what we did. We where idiots
Seen that years ago. It only takes 13-14PSI (gauge) in air to choke the flow. In fact if you ever remove the tire valve in an inflated tire , as it deflates you will hear one sound and then suddenly it will change to a new sound. At that change point, if you put a pressure gauge on it it will read 13-14 psi, the sonic threshold.
RULE OF THUMB if the exit pressure ABSOLUTE is about 1/2(.5283) or less (or~ 2:1)of the stagnation pressure ABSOLUTE (storage pressure) then the flow is choked @ Mach 1
I love stuff like this. The simple or mundane, when looking closer, isn't simple or mundane.
Honestly, I believe it. It explains why those shits are always SO DAMN LOUD, even just the Staples air cans. When I work in the shop, the compressed air is the thing I always wear ear protection for, more than almost anything else.
Weak, I only use safety glasses when required.
(Kidding btw)
Scared folks go to church
genuinely my first thought as well
Good habit! I'm a metal worker and know plenty of people who will shrug it off as "not needing it" ... they'll be surprised when they try to listen to loud music when they're older. 🫠
This has a great mix of everyday observations, concepts I knew of but couldn't ELI5, jerry rigging/jugaad and pretty images that reminded me what got me into science in the first place.
That combined with the numerous big channels by domain experts on a video with ‘only’ 300k views and 9k subs makes it feel like an exclusive club.
I had never heard of shock diamonds and it’s stunning you caught it with your naked eye. Thank you for posting this. I know nothing about your content so I would say don’t assume your viewers know any principle your covering as RUclips recommends people for all sorts of reasons.
Great find. I would love it if you want into step by step about setting up the air circulation imaging diy. That was also pretty incredible to me.
Hey there! I just stumbled accross this video... really cool! Never thought about looking shockwaves in compressed air cans in my workshop, though i worked in aerospace and studied shockwaves for years. Simply amazing! You sir are youtube at it´s best!! BTW, really cool precision machining content, SUBSCRIBED!!!
I love discovering new science things that are in plain sight but never seen, thank you so much for this
earned a sub for the curiosity, persistence, and engineering needed to put this vid together.
Awesome video, and its great seeing a bunch of the science community now looking into this. You sir have just started a new wave of youtube videos
nice thanks. I somehow didn't expect such a simple setup would make schlieren work
Wow so now I know the feeling of the air chuck when it hits my skin felt like a tiny point is hitting my skin and i imagined it like a cone poking me after a few seconds it starts hurting. It's cool to know I was right about it, I'm still surprised I don't remember or ever made the connection that was it.
Thank you I haven't seen anyone show this before. It's amazingly fascinating how the fast moving flow, isn't lamimater flow like I thought. It's actually called "shock diamonds"
The same as the supersonic exhaust from a propelling nozzle on a jet fighter.
Thanks again for making this video!
Yep. Subscribed. That was awesome and I love your approach to it all. Just step back and deconstruct the issue and you arrived at the solution to observing it how you wanted to. Can’t wait to see more videos. Super interesting.
Definitely one of those things when you think about its obvious, but without supersonic flow and the turbulence it creates I'd bet it would make duster less effective. Actually you can see this as the can gets used up/gets cold. Very neat video, finding interesting topics in everyday things.
This is the nerdiest video I've seen this year.
This is SO COOL!
You're telling me I've been blasting my PCs with supersonic air?!
Gases flow out of an ideal nozzle slightly faster than the local speed of sound.
Intuitively explained now. Speed of sound is the speed at which waves can propogate through a fluid. Temperature is a measure of how fast the individual molecules are bouncing around, ricocheting off each other. The two are the same principle, and in fact temperature rather than pressure affects speed of sound. So, speed of sound is the velocity at which molecules can bounce around and transmit motion from the molecule behind them to the one in front.
In the case of supersonic flow, or gas flowing out of an ideal nozzle, there is no barrier of air molecules to bounce off of and transmit motion to, so all molecules end up bouncing around until they get a trajectory that leads them out of the nozzle. All of the molecules are moving in a somewhat laminar flow through the nozzle and out of it.
Now, the speed of sound wasnt the measure of how fast the individual molecules were moving due to their temperature, but how quickly they can complete a round trip of recieving and input from behind them and outputing it to the molecule ahead. The speed they are moving is faster than the speed at which they can complete the whole round trip.
Once all the molecules are flowing through the nozzle unimpeded, they are theoretically traveling at the speed of their temperature, rather than the speed of a closed loop series of collisions. Because we are witnessing or measuring a one way trip instead of a round trip, the velocity is higher.
I'm an automotive painter and I work with compressed air all day. I see shock diamonds coming from my air blower all the time. I see them best on slightly humid days. I don't know this for a fact but they seem to drop off between 60-80 psi of air in the line.
Was great to see you also included simple compressed air rather than just relying on the denser gas to demonstrate the effect in what I assume is ~1 atm of pressure. Doing so increased the value of this video.
Good on you for this. I admire your curiosity and your determination to push for a better Schlieren setup to get crisper photos. Well done.
Real, basic research! Incredible set of experiments! Thank you very much.
This is crazy cool. And even cooler that the who’s who of RUclips science creators are in here too. Great job bro. This is an amazing video!
I had no idea. It's amazing that our skin can withstand a supersonic flow point blank like that.
Amazing! Love your work. From cheap local materials, you are showing very valuable stuff. Thank you.
I did not expect that kind of speed. Thanks for making a video on this.
What a video!! Innovative science puts me on the edge of my seat!!
Seeing the shockwaves was awe inducing. Thank you for the video.
That's really cool work!
I've tinkered enough to know that making a setup like this looks easy, but isn't easy.
You distilled quite a lot of work into a very coherent and intelligent report.
That's awesome, congrats. I learned a lot by watching this.
I've honestly never wondered how fast compressed air left the nozzle. I went from no curiosity to an answer in no time. The future is now!
This is really neat. I've never known those patterns had a name or were a field of study. After I watched your video, I read about the diamonds.
Very unintuitive discovery indeed! I made a video on this a while back. After talking to some NASA aerospace engineers seems the challenge of supersonic wind tunnels is not getting the gas supersonic, but rather controlling the entropy and temperature of the flow to keep things consistent with flight. Thanks for sharing! Excellent video.
This will be fun to ponder for the next few days. Thanks!
There is so much in our everyday life that we just take for granted without looking closer. I appreciate this video a lot.
I saw those shock diamonds as a kid playing with these, I knew that meant it was going fast, but I didn't realize that was something super special
How did you see them?
@@dundermifflinity By looking at the stream in front of a light and squinting. I was a curious kid. You don't need a complicated setup to just see it with the naked eye, you just need a complicated setup to record it on video because cameras aren't as sensitive as our eyes.
@@Ang3lUki nice, must try it
I've long been aware of high pressure through a small aperture doing this, but I thought it eventually levels out (given no moving parts) and the end hole size mattered (the expanded nozzle example).
Neat vid! Thanks for it.
This video just popped up in my feed (I guess the algorithm is working?) and I'm so glad it did! That's fascinating! Who knew that air is coming out of those things so fast! I'm definitely subscribing 😃
That is one of the coolest things I’ve learned in a while. Thank you so much for diving into that and sharing with us!
I think it is important to point out that the canned air, not actually being air, has a much lower speed of sound. You point out that the speed of sound does change. But these effects are pretty significant at 223K and 5 atm, the speed of sound is easily halved (compared to air at STP). They get even lower if the pressure is greater than 5 atm. There is a really neat article about this published last year [Speed of Sound in Gaseous 1,1-Difluoroethene (R1132a) at Temperatures Between 193 K and 383 K at Pressures up to 3 MPa (Demirdesen 2023)].
Notably, this only applies to the can but I think the lower speeds from the can is kinda intuitive.
The beauty in everyday tasks and objects never ceases to amaze me... There is so much happening that we never get to see.
As soon as you have more than a factor of ~2 (it is 1/0,528, iirc) in pressure difference at a nozzle, you get supersonic flow. Against atmospheric pressure this means that you only need ~2 bars for supersonic flow.
A small laval nozzle can speed it up a little more, but with cold gas you won't get very high in mach numbers.
youtube has been spamming this video in my for you section for a week, glad I finally watched it, very cool!!
We do fluid dynamics research and use these gas cans to check our shadowgraph alignment. It's so common to see the diamonds that we think it's mundane. Sometimes we don't realize how good we have it...
This was crazy informative. Extremely interesting. I was as shocked to learn as you were these characteristics existed.... amazing
Thats very beautiful, and surprising! I never would have expected I'm working with supersonic flow every time I'm tinkering around in my garage.
Guys got canvas open in the background 😂 keep up the good work man I hope college is going well for you!
My first thought was: I have no idea what the answer is, but surely, speed of sound is a safe upper bound ... Being completely wrong is so much fun!
I've noticed working with compressed air at high pressures, that I've actually seen some sort of refraction of light, and I thought that is the strangest thing, "How would something like that be possible, it's just air? I should research it" thank you for this video.
How cool !!! I never thought anything about it....Thank You for sharing this
Glad that this video was suggested to me and furthermore glad that I decided to click on it. Good stuff. Love ya. Bye
Would really like to know an actual speed number! That’s super cool! Thanks for sharing your discovery!
This sort of video was what youtube was made for. Love it
Outstanding bit of investigation and super results from the improvised photographic set up... Very impressive results! And cool as 'ell.
this is crazy! but what’s super cool is that this video has brought lots of massive science youtubers to the comments to share their enthusiasm on a small channel! awesome 🙌
That's an awesome find! Thanks for taking the time to put together and share that!
First few minutes in I was going to call BS. Happy to be proven wrong. Great information.
You got upvotes from some of my favorite RUclipsrs. New subscriber!🎉
Really cool to see the shock waves reflect off of that corner and expand past it
i also wish most science videos would be this straight forward too
Very cool! In a strange coincidence I published a video a week or so ago where my friend demonstrates the Schlieren effect. I'd never heard of it before. BTW, I referred your channel to him and he really likes it.
This is incredible. Thanks for sharing this discovery and the steps you took for that closer look. Nice.
I hadn’t thought this would be possible until seeing this video, but now I’m absolutely positive that the air released from a semi-truck’s air brakes when the parking brake is engaged also has Mach diamonds in the airflow. The reason I’m sure is because if you’re standing next to the truck when the driver pulls the brake it’s loud enough to cause physical pain within the ears. The sharp hissing sound is at least 130 decibels, if not more.
Have tired reflector schlieren setups but didn't realise refractory lenses can also be used.
Looks like you can easily get very high quality schlieren setups like this.
Thanks!
"schockwaves are just step waves in density" i cant stop thinking about how brilliant this statement is
I noticed this a long time ago but just assumed it was due to my astigmatism! Glad to know I wasn't crazy or blind!
Another example showing that the algorithm knows me too well
Super interesting! I had never even thought of the possibility that air dusters accelerate the gas so fast that it's supersonic. Finding videos and channels like this is my favorite thing about RUclips. The channels Applied Science and The Thought Emporium are also goldmines for stuff like this.
Fascinating! Thank you for sharing your knowledge!
love the title of the video. anti-clickbait, but leaves the question. also super interesting explanations. never really considered that the speed of sound varies based on temperature. mind blowing to a fool like myself
It's kinda crazy that in the US the most common propellants used in canned air are HFCs. In the EU you'll be pressed to find any of that, it's all just propane-butane for the most part. That does make it flammable, so I understand the advantages of HFCs, but in most cases (especially home/hobby usage), I'm not sure they really outweigh the damage they do to the climate.
Bold of you to think the primary cause of the impending climate collapse cares about what it continues to do to the entire future of humanity.
It's kinda funny actually how the regulations around it are as well. It's highly illegal and you'l get a nasty fine if you intentionally vent even small quantities of HFC refrigerant. But we sell cans of refrigerant you use to dust things off by the thousands of tons. WAT. Sure, it won't put holes into the ozone.... but R-152a, aka Difluoroethane, is around 1200x as potent of a greenhouse gas as CO2 of I remember correctly. It's still mildly flammable as well, and CAN ignite if used in decent quantities near a ignition source. Combustion byproducts are mainly carbonyl fluoride, hydrofluoric acid, and carbon monoxide. One breath of that will leave you with a trip to the ER, from a few reports I read. At least butane would only cause a small fire, there's no way we should be using refrigerant as duster spray. I'd like to have it banned for use as a duster.
I love your ability to spin up an experiment like that. Impressive
A very easy schlieren effect can be seen when sunlight reflects off a convex surface like a car windscreen. I noticed this when my car was parked in just the right spot for the reflection from the windscreen to shine into my workshop through the doorway and project onto the back wall. You will see the best results if you can darken the room by covering any windows etc. The divergent rays of light would show a shadow image which revealed the air currents produced from a blow torch. You could even see the convection current produced from the warmth of your hand if the air temperature was cool enough. To see this you need to place the item being studied about a foot or so from the surface that the image will project onto. This would probably work with a concave mirror as long as you are reflecting the light onto a surface a minimum of twice the focal length of the mirror. The plus to this method is that you have a large area that the image can be seen.
I don't know much but I do know that if you're drinking beer with the neighbor and discover his blow gun and air compressor in the garage, you can put one of those little darts through a tree.
Fantastic observation and great video!
Lovely to see that all the scientific channels are here because they too are interested in this topic,/ in science.
This is amazing I never expect it to be supersonic either.
great channel cant wait to see where you take it.
I jumped at this video thinking I saw shock diamonds in the thumbnail and was NOT disappointed.
I am a simple man. I see shock-diamonds, I click.
this explains how people are killing sensitive electronics that have fans when trying to dust them. too many people dont realise that if you dont hold the fan from spinning the fan motor will generate electricity. since your blowing air on them at supersonic speeds, its entirely possible that the fans could end up spinning faster then they are designed to and generate more voltage/current then the circuit is designed to handle and then fry components.