Smoke Ring Propulsion

as a kid i remember watching a documentary about futuristic aircraft technologies and this documentary briefly featured a small shiny flying saucer looking thing that would launch up into the air using the power of a laser beam that was mounted on the ground the laser beam is made up of infrared light as the beam pulses it strips air molecules of their electrons creating an explosive plasma that propels [Applause] now i'm not quite sure how this technology worked and i would be extremely optimistic to think that i could replicate it myself but instead of using a laser beam to launch this thing into the air what about if we used vortex rings this video is sponsored by curiosity stream more on them later now i know you can't really compare a laser beam to the movement of air but a vortex ring is kind of a focused portion of air that travels over long distances a little like a laser beam whereas a regular blaster there is more like a torch or a light bulb where it disperses out a lot sooner and doesn't travel as far so let's build a vortex cannon and run some tests to produce the vortex rings we need a rapid blast of air so i've chosen to use these cheap solenoid valves that open when hooked up to a 12 volt power supply however to make sure the valve opens and closes within a split second i've made this control board which is essentially an electronically timed switch to open and close the valve in about 30 milliseconds the only problem with these cheap valves is it appears they have a large input and output from the outside but if you disassemble them the actual valve portion has a much smaller diameter and therefore restricts the airflow so i'm going to hook up four valves together to increase the burst of air hopefully resulting in a higher power vortex after mounting the valves together on a stand i 3d printed a manifold that will connect all the outputs into one large nozzle speaking of nozzles we need to figure out how to turn this burst of air into a vortex ring from watching videos online it seems there are two main ways to creating vortex rings the first is to use what i call a rubbish bin because it would make a rubbish bin with such a large hole this is an easy method to make vortex rings as it only requires a plastic sheet attached to the rear and a small push to create the vortex however they don't seem to move with much velocity the second type is a cone nozzle which often uses a combustible fluid to create a sudden burst of air and these seem far more powerful i think some places even use these to break up hailstorms to prevent crops from being damaged so they have some decent range too so i 3d printed a cone nozzle to attach to the valve manifold and it's ready for a first test well that wasn't quite what i expected maybe the valves aren't providing a large enough burst of air for this huge nozzle so let's try a smaller cone equally disappointing however with a few modifications to the valve manifold it was starting to show some potential i then decided to scrap the cone design and try the bin with a hole method where all four valves were plumbed into a small chamber with a hole at the end to see if this would produce a better vortex and well it didn't i think the problem here is that the valves can't open and more importantly they can't close fast enough so instead of it being like a pop of air it's more like a of air which creates way too much turbulence and therefore destroys the vortex rings but i have a theory of how to get around this if we take a look at the first cone nozzle the air will flow out of the valve at very high speed and slow down as it expands along the length of the cone and because it slows down my theory is this causes the length of the pressure wave to shorten i'm not 100 sure if this is how it works but i kind of view it like when watching a race on the straights they all look really spread out because they're traveling at high speed but as soon as they slow down for a corner they all bunch up together but the issue is this results in a really slow moving vortex ring and the problem with the second design is it didn't have much of an expansion section so all the air would flow out at high speed and cause too much turbulence for the vortex to form but what if we combine the two designs and had a long expansion section that would allow the pressure wave to shorten and then at the end there would be a narrower section with a hole to accelerate the air again and create a faster vortex so i printed this exact design and gave it a test [Music] and there we have it an almost perfect vortex ring the timing of the valves produced the perfect burst of air to form the ring and nothing more leaving a very little trailer smoke behind the only problem is they still don't move as fast as i would like them to and they tend to stop moving after about three meters on the topic of fluid dynamics i recently came across an educational series called butterfly effect which explains all sorts of science concepts over on curiosity stream it's kind of like netflix but for nerds which is way better as there's thousands of movies and tv shows that cover science history technology and many more like this episode of butterfly effect which is all about fluid dynamics from the history of how ancient romans discovered density and buoyancy all the way up to the cowanda effect and bernoulli's principle that play a huge role in how aircraft fly and there are so many more documentaries and educational episodes to choose from because as the name describes curiosity stream is here for people who want to know more so if you're one of those people you can watch these on your mobile computer browser smart tv and a range of other devices by signing up for just 14.99 for a whole year using the code tom stanton or by clicking the link in the description down below so to increase the speed of the vortex rings i made a new nozzle with essentially the same design but with the smaller diameter exit which allows me to fit different size caps to test the best size and speed of the vortex which resulted in a much faster vortex ring and even a few trailing rings that would eventually break up due to turbulence and this created one of my favorite slow-mo shots where the secondary ring gets sucked into the first ring and knocks outwards slightly it looks like there's some complex and interesting fluid dynamics going on here and i'm not sure why there are multiple rings being produced it could be due to the valves opening at different times or maybe the pressure wave is bouncing back and forth inside of the expansion chamber either way it looks really cool so now we need to build some kind of sail that will capture the vortex ring and propel itself into the air but judging by the current performance of the vortex rings it's going to need to be very lightweight so i've designed this dome-shaped sail with a point in the middle with the theory that the vortex will flow into this cone and be pushed around the curvature and redirected backwards for thrust and because i've designed this using the sheet metal tool in fusion 360 i can flatten out one of these sections which allows me to 3d print it as a template that can be used to cut out the perfect shape from lightweight paper then after carefully taping the sections together we get a slightly flimsy dome shape of what i designed earlier i then mounted this dome sail on a string and fired a vortex at it which looked quite promising at first but from watching the slo-mo footage it was clear that most of the movement was caused by the secondary blast of air and not the actual vortex so i moved the sail a bit further away to make sure only the vortex would hit it and well it was far less impressive but i also wonder if the straw riding along the string causes too much friction especially if the sail is twisted by the vortex so i suspended the sail by two lengths of string to hopefully reduce any friction this resulted in the sail moving much further with just the push from the vortex but it also revealed two more issues the first being the amount of energy absorbed by the sail flexing probably isn't very efficient and the second is the accuracy of this vortex cannon it's mounted maybe a meter or so away from the sail and fails to hit the center of the sail maybe 80 percent of the time which causes the sail to be thrown way off to the side so at any decent range is going to be almost impossible to hit such a small target and guess what i decided to do next build a smaller sail this was mostly to reduce the weight and flex of the sail then the accuracy issues can be removed by running the tests multiple times until the vortex hits perfectly which was easier said than done however when the vortex did hit perfectly it revealed some awesome slow motion shots like this close-up shot filmed at 6 000 frames per second shows the vortex continued to spin even after making contact with the sail so now all we need to do is mount this whole setup vertically to try and launch the sail upwards into the sky but if you're wondering why i spent so long trying to make this electronically controlled solenoid vortex cannon it's because it allows me to fire multiple rings per second for more thrust okay this is the first test with about 12 bursts of air per second [Music] that sounds so good it may sound impressive but from the slo-mo footage it was clear the rapid fire of the rings was causing a lot of turbulence in the surrounding air which ends up with the following rings being shot all over the place so let's see if this will even lift the sail it seems it lifts the cell reasonably well with the first vortex when it hits the center of the sail but as soon as one hits off center it twists the straw on the string and causes too much friction you can still see the vortex rings hitting the sail with a decent amount of force but they're just not accurate enough to move it any higher but one way to remove any accuracy issues is to use just a regular blast of air instead of a vortex and we haven't even considered the stability of the sail yet [Music] [Music] you

Channel: Tom Stanton

Views: 988,131

Keywords: vortex, propulsion, physics

Id: cJoUSHJcV4E

Length: 11min 0sec (660 seconds)

Published: Wed Feb 23 2022