When Vortex Rings Collide

Intrigued by a grainy video from 1992, [Destin] from Smarter Every Day decided to jump in and fund his own research into the strange phenomenon of vortex ring collisions.

This hack started with a scientific publication and a video from back in 1992. The paper, written by Dr. T T Lim and TB Nichols, illustrated what happens when two vortex rings collide perfectly head-on. The rings collide and spread out forming a thin membrane. Then smaller rings form at a 90-degree angle to the original collision. It’s a beautiful effect when created with multicolored dye in water. But what causes it? There are theories about the fluid mechanics involved, but not much research has gone on since Dr. Lim’s paper.

[Destin] wanted to find out more about the effect, and get some video of it. Being the guy behind Smarter Every Day, he had the high-speed photography equipment and the funds to make that happen. Little did he know that this passion project would take four years to complete.

The initial prototype was built as part of a senior design project by a group of college students. While they did show the phenomenon, it was only barely visible, and not easily repeatable. [Destin] then got an engineer to design and build the experiment apparatus with him. It took numerous prototypes and changes, and years of development.

The final “vortex cannons” are driven by a computer controlled pneumatic cylinder which ensures both cannons get a perfect pulse of air. The air pushes a membrane which moves the dye and water out through an orifice. It’s a very finicky process, but when everything goes right, the result is a perfect collision. Just as in Dr. Lim’s video, the vortexes crash into each other, then form a ring on smaller vortexes.

Destin didn’t stop there. He’s made his data public, in the form of high-speed video – nearly 12 hours worth when played at normal speed. The hope is that researchers and engineers will now have enough information to better understand this phenomenon.

You can check out the videos after the break. If you’re a Smarter Every Day fan, we’ve covered [Destin’s] work in the past, including his backwards brain bike and his work with magnets.

Continue reading “When Vortex Rings Collide”

Just When You Thought Magnets Weren’t Magic; Magnets Are Mechanisms

This is magic, big news, both, or neither. It’s so exciting to see magnets behave in this bizarre and wonderful way that we think it’s hard to forecast where this will go. Shown above is a pair of magnets that have several modes of operation. They attract each other, but repel when less than a centimeter apart. However, give one a twist and the two will strongly attract.

The behavior is thanks to a new process of 3D printing magnets to manipulate where the fields occur. With the behavior just described, they would function well as a cabinet latch which has soft close and positive lock, all built into two magnets.

This comes from one of our favorite YouTube channels, [SmarterEveryDay], who just toured Polymagnet — a company that has figured out how to actually print magnetic fields.

3dprinted-magnets-thumbSo how the heck does it work? Well, your standard magnet has a north face on one side, and a south face on the other — creating a magnetic loop between the two. But what if you could put north and south on the same side of the magnet, and vary their position and size? It means you can control the magnetic field down to the magnetic pixel, or as Polymagnet calls them — a Maxel.

Here you can see some magnetic film (which reacts visually to magnetic fields) put on top of the two parts of the demo magnet. The printed design is very similar to a mechanical mechanism. We’d explain more, but [Destin] does a great job teaching about the tech in the video found below.

Is this the dawn of magnetic mechanisms? We certainly have never seen anything like it.

Continue reading “Just When You Thought Magnets Weren’t Magic; Magnets Are Mechanisms”

Try Not To Fall Off The Backwards Brain Bike

[Destin] of SmarterEveryDay fame has a challenge for your brain : a bicycle where the handlebars turn the front wheel in the opposite direction of a typical bike (YouTube link). For example, turning the handlebars left turns the wheel right and vice versa. He warns you it’s harder than it looks.

The hack that pulls this off is a simple one compared to bike hacks we’ve previously covered. Gears on the head tube make this possible. It was built by his welder friends who challenged him to ride it. He couldn’t at first; determined to overwrite his brain’s memory of bike riding, he practiced until he finally succeeded. It took him eight months. When it was time to ride an old-fashioned bike, it only took him about twenty minutes to “un-learn” the Backwards Brain Bike. [Destin’s] biking illustrates neuroplasticity, memory, and learning in a fun way (fun for us; no doubt frustrating for him).

As a testament to the sponge-like brains of youth, [Destin’s] son learned to ride the Backwards Brain Bike in only two weeks.

Continue reading “Try Not To Fall Off The Backwards Brain Bike”

Hackaday Links: February 22, 2015

We met up with Freescale guy [Witek] at our party in Munich last year, and he wrote in to tell us about the Freescale booth at Embedded World this week in Nuremberg. They’re going to have a bunch of Freedom boards to play around with and an extremely powerful RIoTboard with a 1GHz iMX6 Solo processor, 1GB of RAM, and 4GB of EMMC Flash. It’s not a Raspi or BeagleBone killer, but if you need a small Linux board with a lot of horsepower, there ‘ya go.

SmarterEveryDay is finally getting around to doing a series of videos about space. This guy knows his stuff, and with the access he can get, it should make for interesting viewing.

Here’s something for your Sunday listening: [Vint Cerf] at Carnegie Mellon talking about the Olive Project and the Interplanetary Internet. The Olive project is an archive for executables, and solves the problem of having to preserve hardware along with software. Cool stuff.

10 GHz pulse magnetron destroys electronics. That’s the only information you’re going to get with this one. There’s a fine line between ‘don’t try this at home’ and ‘this project needs replication’.

Most of the northern half of the United States is covered in a billion tons of snow. [Jamie]’s electric snowmobile/Power Wheels is the perfect vehicle for this occasion. It’s 36V with two 500W motors. Figure out how to replace the wheels with small treads, and there’s really something interesting here.