If we study the laws of fluid motion from physics, and write a computer program that
contains these laws, we can create wondrous fluid simulations like the ones you see here.
The amount of detail we can simulate with these programs is increasing every year, not
only due to the fact that hardware improves over time, but also, the pace of progress
in computer graphics research is truly remarkable.
So, it s there nothing else to do?
Are we done with fluid simulation research?
Oh, no.
No, no, no.
For instance, fluid-solid interaction still remains a challenging phenomenon to simulate.
This means that the sand is allowed to have an effect on the fluid, but at the same time,
as the fluid sloshes around, it also moves the sand particles within.
This is what we refer to as two-way coupling.
Note that this previous work that you see here was built on the Material Point Method,
a hybrid simulation technique that uses both particles and grids, whereas this new paper
introduces proper fluid-solid coupling to the simpler, grid-based simulators.
Not only that, but this new work also shows us that there are different kinds of two-way
coupling.
If we look at this footage with the honey and the dipper, it looks great, however, this
still doesn’t seem right to me.
We are doing science here, so fortunately, we don’t need to guess what seems or doesn’t
seem right.
This is my favorite part, because this is when we let reality be our judge and compare
to what exactly happens in the real world.
So let’s do that!
Whoa!
There is quite a bit of a difference, because in reality, the honey is able to support the
dipper.
One-way coupling, of course, cannot simulate this kind of back and forth interaction, and
neither can weak two-way coupling pull this off.
And now, let’s see, YES!
There we go, the new strong two-way coupling method finally gets this right.
And not only that, but what I really love about this is that it also gets small nuances
right.
I will try to speed up the footage a little, so you can see that the honey doesn’t only
support the dipper, but the dipper still has some subtle movements both in reality and
in the simulation.
A+.
Love it.
So, what is the problem?
Why is this so difficult to simulate?
One of the key problems here is being able to have a simulation that has a fine resolution
in the areas where a fluid and a solid intersect each other.
If we create a super detailed simulation, it will take from hours to days to compute,
but on the other hand, if we have a too coarse one, it will compute the required deformations
in so few of these grid points that we’ll get a really inaccurate simulation, and not
only that, but we will even miss some of the interactions completely.
This paper proposes a neat new volume estimation technique that focuses these computations
to where the action happens, and only there, which means that we can get these really incredible
results, even if we only run a relatively coarse simulation.
I could watch these gooey, viscous simulations all day long.
If you have a closer look at the paper in the description, you will find some hard data
that shows that this technique executes quicker than other methods that are able to provide
comparable results.
Thanks for watching and for your generous support, and I'll see you next time!