Dear Fellow Scholars, this is Two Minute Papers with Dr. Károly Zsolnai-Fehér.
You’re in for a real treat today, because today, once again, we’re not going to simulate
just plain regular fluids.
No!
We’re going to simulate ferrofluids!
These are fluids that have magnetic properties and respond to an external magnetic field
and get this, they are even able even climb things.
Look at this footage from a previous paper.
Here is a legendary real experiment where with magnetism, we can make a ferrofluid climb
up on this steel helix.
Look at that.
And now, the simulation.
Look at how closely it matches the real footage.
Marvelous, especially that it is hard to overstate how challenging it is to create an accurate
simulation like this.
And the paper got even better.
This footage could even be used as proper teaching material.
Look.
On this axis, you can see how the fluid disturbances get more pronounced as a response to a stronger
magnetic field.
And in this direction, you see how the effect of surface tension smooths out these shapes.
What a visualization!
The information density here is just out of this world, while it is still so easy to read
at a glance.
And it is also absolutely beautiful.
This paper was a true masterpiece.
The first author of this work was Libo Huang and it was advised by Prof. Dominik Michels
who has a strong physics background.
And here is the punchline: Libo Huang is a PhD student and this was his first paper.
Let me say it again: this was Libo Huang’s first paper and it is a masterpiece.
Wow!
And it gets better, because this new paper is called Surface-Only Ferrofluids…and YES!!!
It is from the same authors.
So this paper is supposed to be better, but the previous technique set a really high bar.
How the heck do you beat that?!
What more could we possibly ask for?
Well, this new method showcases a surface-only formulation, and a key observation here that
for a class of ferrofluids, we don’t have to compute how the magnetic forces act on
the entirety of the 3D fluid domain, we only have to compute them on the surface of the
model.
So what does this give us?
One of my favorite experiments!
In this case, we squeeze the fluid between two glass planes and start cranking up the
magnetic field strength perpendicular to these planes.
Of course, we expect that it starts flowing sideways, but not at all how we would expect
it.
Wow.
Look as how these beautiful fluid labyrinths start slowly forming.
And we can simulate all this on our home computers today.
We are truly living in a science fiction world.
Now if you find yourself missing the climbing experiment from the previous paper, don’t
despair, this can still do that, look.
First, we can control the movement of the fluid by turning on the upper magnet, then,
slowly turn it off while turning on the lower magnet to give rise to this beautiful climbing
phenomenon.
And that’s not all, fortunately, this work is also ample in amazing visualizations, for
instance, this one shows how the ferrofluid changes if we crank up the strength of our
magnets, and how changing the surface tension determines the distance between the spikes
and the overall smoothness of the fluid.
What a time to be alive!
One of the limitations of this technique is that it does not deal with viscosity well,
so if we are looking to create a crazy goo simulation like this one, but, with ferrofluids,
we will need something else for that.
Perhaps that something will be the next
paper down the line.
Thanks for watching and for your generous support, and I'll see you next time!