Avalanches Simulated With 500,000 Ping-Pong Balls

An anonymous reader submits "Ping-pong ball avalanche experiments have been carried out for the last three years at the Miyanomori ski jump in Sapporo, Japan, to study three-dimensional granular flows. Up to 550,000 balls were released near the top of the landing slope. The balls then flowed past video cameras positioned close to the flow, which measured individual ball velocities in three dimensions, and air pressure tubes at different heights. The flows developed a complicated three-dimensional structure with a distinct head and tail, lobes and 'eyes.' See for yourself, it's quite interesting!"

Comments

wtf?

[kurosawdust]

I am very saddened that these people never thought of using this setup to simulate something orders of magnitude more profitable - the lottery!

"Hey Bill, we've got tons of ping-pong balls and a very elaborate and sophisticated means of tracking their movement - what should we do with them?"
"Uhh, use them to predict the Powerball results and retire on private carribean islands, unique ones of which we own for every day of the month?"
"No, you fool! Avalanche research is clearly the way!"

A victim of this experiment?

[weeboo0104]

The only tragic victim of this experiment was this man.

A bespecticled bunny rabbit and moose were seen running from the scene.

The hardest part...

[stefanlasiewski]

I hate ping pong avalanches.

The hardest part is digging yourself out with nothing but a ping pong paddle...

Hmm...

[shadowbearer]

This is an interesting experiment and all, but it resembles a real avalanche about as much as computer climate models resemble real weather.

A actual avalanche is orders of magnitude more complicated. It'd probably be easier, and much more informative, to simulate it on a computer, actually.

It does make for some good eye candy, tho, and I'd bet it was a whole lot of fun. As a serious scientific tool, it's probably not very effective in this day and age, given the better tools out there.

As a teaching tool, however, it has astounding potential, especially in primary education.

Just as an aside, I've witnessed a few large avalanches. I was fascinated (and horrified) at the time; the fascination came from observing the complex flows introduced by various things such as the underlying terrain, trees, assorted rocks, etc. I remember thinking the last time that it was a good demonstration of fluid flow dynamics. The horror came from watching several skiers get caught up in the snow flow. They survived, thank Guh.

(Disclaimer: IANAMathematician).

SB

Re:Hmm...

[mhesseltine]

From a recent article in DesignFax Magazine, you might be surprised at the kinds of things you can model using simple bouncing-ball-like objects. Everything from giant dump trucks to laser toner.

Re:Hmm...

[Cecil]

A actual avalanche is orders of magnitude more complicated. It'd probably be easier, and much more informative, to simulate it on a computer, actually.

The same thing could be said about an avalanche relative to most of our fluid dynamics models. It is still orders of magnitude more complicated. Which isn't to say that our models aren't quite accurate, they are. But at the same time, they're merely a 'good enough' oversimplification of what's really going on.

Fluid dynamics are an extremely difficult thing to model, and even more difficult to compute. They could challenge most of the supercomputers on the top500 list.

In fact, the top computer on there, Earth Simulator, (at well over double second place) has one of it's two primary objectives being the calculation of relatively simple fluid dynamics models across the Earth's entire oceans.

So, to put it summarize my point here, the best fluid dynamics models we have are extremely expensive to compute, and they are still not perfect. The best way to better understand, and therefore better model, what is happening, is still to experiment with real physics. This experiment will help us develop faster-but-still-accurate models, or extremely precise models for fluid behavior. Either way, recording the locations of each 'particle' as they flow is actually research and will provide a solid set of data for future research to build on.

Disclaimer: I work in the petroleum industry, and therefore only have experience with extremely high pressure/small scale fluid dynamics. My extrapolations may not hold true to the broader field of fluid dynamics.

Re:Hmm...

[gtapang]

That is true. Aside from the difficulty in simulating such systems, it is also hard to do an actual experiment that will correspond exactly to your simulation.

Furthermore, a model is exactly what it is-- an approximation of your actual complex system. There would be some details that would be left out to simplify the model while keeping the interesting phenomena intact.

Using an actual system like the ping-pong experiment would still be an approximation to an actual avalanche but it provides a reasonably controllable situation and a level of detail that would be accessible to the investigators. And it generally would proceed much faster than simulating it in a computer.

We were in a similar situation in a research involving escape panic dynamics where the behaviour of agents (read: people) moving out of an enclosure were looked into. This would be akin to looking at the exit dynamics of people in a fire or in a football stadium in a a riot.

We did simulate escape panic but later on we used mice to look at the models in a real system. It turns out that the model reasonably gets some of the features of the dynamics but would miss out on things not explicitly included in the model, like herding behavior.

Mining Simulations

[trinitrotoluene]

I went to the Open House for the mining engineering program at my university (Queen's) and one of the professors showed us how they use computer simulations to model rock interactions. The simulations modelled the behaviour and interactions of thousands of sample rock particles. Really interesting stuff. I guess this kind of test is where they get the raw data to develop these computer models.

Mining engineering is also cool because there is a required explosives and blasting course in second year.

Avalanche Rescue

[fuzzybunny]

This is pretty cool, sort of an "avalanche light" experience.

They could rescue people with chihuahuas carrying cans of diet pepsi.

Re:looks like...

[jafuser]

Maybe this means we can use badgers to predict avalanches! =)