The next time you're in the shower, try pouring a steady stream of shampoo into an open, flattened palm. See how the thread loops and buckles as it comes into contact with your hand? Physicists who study fluid dynamics call this behavior "the rope-coiling effect;" it's a physical property commonly observed in viscous fluids (like shampoo) when they're poured from a nozzle onto a flat surface (like your hand).

Now direct your attention to the video up top. In it, University of Toronto physicist Stephen Morris and his colleagues have replaced the crude conditions of your shower-laboratory with an apparatus capable of much greater experimental precision. Morris' viscous fluid is dispensed at a uniform rate from a nozzle positioned at a set height onto a much flatter surface than the palm of your hand. And to make things extra interesting, Morris and his colleagues have replaced the stationary surface of your palm with a motorized belt, the speed of which can be varied.

In doing so, Morris and his colleagues note that "the rotational symmetry of the buckling instability is broken, and a wealth of interesting states are observed." Fuck Yeah Fluid Dynamics walks us through the changes that we see in the video:


Beautiful stuff, right? Hooray for shower physics!


[arXiv via Fuck Yeah Fluid Dynamics]
Sinusoidal waveform via Wikimedia Commons