Have you seen... [laminar fluid flow]
Saturday, October 22, 2011 at 10:00 The video below is not the most dramatic or exciting... until a subtle surprise at the end.
Here's how it starts: drops of three colored fluids are placed in a small container of water. A crank is turned at the top that forces the water to circulate. After a 6 1/2 revolutions the colored drops of liquid are pretty well "mixed" and the person stops, then starts turning the crank slowly and steadily in the opposite direction...
Cool huh? You might think this was just video done in reverse, to get the colored drops to re-form like that.
But it is the result of highly laminar flow -- very little turbulence (mixing) -- that keeps everything "in parallel" and the "mixing" therefore becomes a "reversible" action! (Note that this demonstration is also enabled by the fact that the colored liquid drops have a higher viscosity than the surrounding water.)
One can take advantage of the steady, parallel properties of laminar flow in water fountains.
By ensuring laminar behaviour, water streams will hold their shape. Even further, light can be projected onto or into the stream (where it reflects back & forth inside the stream) -- this creates neat visual effects.
It can be mesmerizing.
The water fountain in the next video adds two more tricks to the show. First, the water is pulsed on & off to give a projectile-like effect, Second, some water streams are aligned so that they collide in midair, and where they meet become a shower of (turbulent) droplets. This was installed at a casino, no surprise there!
I 've enjoyed a similar fountain at the Detroit Airport during some travels. Hope to see more around.
