(Click on applet to activate it.)

a, z - in-/decrease rotation speed
s, x - in-/decrease water pressure
d, c - in-/decrease frame rate
of animation
t - toggle tracing
f - toggle reference frame
(switch camera)

Coriolis Fountain

The first exhibit prototype I built in Second Life to try out The Tech Virtual was the Coriolis Fountain. However, I soon hit my limit trying to script that prototype as an interactive, so I decided to use Processing for a more accurate simulation.

Imagine a circular water pipe rotating freely in the horizontal plane, with five nozzles shooting water towards the centre of that ring. If the ring is stationary, all five jets of water meet in the centre. But once you start turning the ring, the jets start bending. What is surprising to most people is the direction in which they bend...

This apparent deflection of the water is partly explained by the Coriolis effect (the result of viewing a straight movement from a rotating reference frame) and partly due to us observing a continuous stream of water rather than just one moving droplet.

In this slow-motion simulation, the water jets are represented by chains of droplets, and you can control the rotation speed of the ring and the water pressure (ie the speed of the water emerging from the nozzles). You can also trace an individual droplet to verify that it indeed travels in a straight line. And finally you can switch reference frame: you can look down at the fountain through either a camera attached to the ceiling (ie as a stationary observer) or a camera mounted to a frame attached to the ring (ie sitting on the ring and turning with it).


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