Natural Disasters

The Project

This project demonstrates some basic concepts of animation applied to different natural disasters. Some physical properties of the disasters have been modified to make a more visibly pleasing demonstration

The Pieces

Lightning

Not much is known about the physical properties of lightning pathing. However, we do know that lightning is most often the cause of the buildup of negative electrical charges. We also know that lightning travels from the ground up, often multiple times. The different strikes are nearly imperceivable, except as a slight quiver. Finally, we know the way lightning moves down is by building up charges and then splitting when too many similar charges are grouped, thus causing lightning to fork.

In my project, I use a random generation of a lightning tree, where the root reaches the destination (the tree) and simulate the lightning strike from top-down, since the difference is negligible. Finally, I applied some noise to make the lightning appear to 'quiver' as stated earlier, although on a much larger scale for noticability. To improve this project, I could implement conservation of momentum when branching, as well as remove the spline curve, since lightning moves more linearly.

Fire

Much more is known about the physical properties of fire. Fire is caused by the consumption of any fuel source and then combustion of the fuel source. The smoke is caused by deterioration of the objects around the fire due to the intense heat. This leaves a 3D fluids problem with the difficulty being in finding the boundary between the fire and its fuel.

This was beyond the scope of my simulation. However, I was able to apply some explicit Euler physics into the fire. I applied two forces. First, there is a horizontal dampening on the fire. Second, I applied an updraft equal to twice the dampening force vertically. The large amount of upwards force applied to the fire was to make it appear as though the fuel of the fire was being supplied by the log

Rain

Rain is probably the easiest to simulate (apart from lighting), but the least visible of all of the disasters. First, the average diameter of a drop of water is about 5mm. Next, the density of a drop is estimated to be about 7.8e-7. Then, the terminal velocity of a raindrop with radius 2.5mm (5mm diameter) is about 26m/s. Finally, the angle at which rain falls is given by the following set of pairs of wind speed (mph) and rainfall angle (degrees):

{(10, 22), (20, 39), (30, 53), (40, 61)}

In my simulation, I tried to accomodate each of these features while making all of them actually visible since raindrops are so small. I set up and solved a best-fit for the data and came up with the follwing equation:

-2.25f * w * w + 24.35f * w - 0.25f, where w = wind speed / 10

To improve the rain, I could have simulated it as lines rather than individual particles since the bottom of the droplet is displaced by air resistance. Further, I could have had the rain splash against the ground.