Predicting Hurricane Irene’s Floods

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As I sit here in New Jersey, of which thousands of acres are under sea level, let us hope that Hurricane Irene does not unleash her wrath upon us hapless citizens…

If Hurricane Irene does hit us full force, would it look like this?

A recent article in Science, “Computational Physics in Film” reminded me how far we have advanced in computer simulation – all based upon basic physics of fluid dynamics.

Exoticmatter NAIAD City flood from Igor Zanic on Vimeo.

A spectacular example blending fluid dynamics and art: “Naiad City Flood”:

Some of the most spectacular examples of physics in film involve fluids, where non-linearities in the underlying Navier-Stokes equations that describe fluid motion lead to accumulation of remarkable geometric complexity.

Computer-based algorithms for animation offers more than speed, efficiency and beauty:

This approach not only is less expensive than filming live action but also can avoid putting actors and crews in dangerous settings and can allow visualization of the impossible.

For the mathematically-inclined, the equation below is used to describe Navier-Stokes:

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How did Igor Zanic manage to use fluid dynamics to create this spectacular animation {simulated using 45 million particles)?

According to Igor:

Igor comments on his test (which was his first Naiad simulation):
“Everything was done on i7 950 3.05Ghz with 12GB ram, for this test Naiad use only 4-5GB. The primary fluid simulation comprised 45 million particles (although I could have run a bigger sim on my system) took 32.5 hours, and produced 156.2GB of data.”
“28 million secondary splash particles produced 55GB of data. I used Naiad’s Particle-Mesh surfacing operator to produce the fluid surface mesh, which weighed in at 20GB for all 300 frames.”
“In the end, everything was converted to .bgeo files for Naiad’s best companion: Houdini, using Van Aarde Krynauw emp2geo plugin http://www.gitorious.org/geo2emp/geo2emp.”
“The fluid mesh was rendered with Clay shader, the splash particles were rendered as points with delayed load and deepshadow maps, and the city was render with Mantra PBR.”

Can’t wait to see what’s next? What do you predict?

A version of this article was published here.

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