The liquid rope coiling effect


Pour syrup onto a pancake and you’ve probably witnessed the elongated thread coiling itself into loops, a phenomenon called the “liquid rope coiling effect”. Scientists have studied this effect for some time and made a number of peculiar observations: for example the frequency of coiling depends in a complicated way on the fall height.

Now Stephen “Sticky Fingers” Morris from the University of Toronto and a few pals have an interesting new take on the problem. They’ve been a-starin at the way a thread of syrup falls onto a conveyor belt, which has the effect of tracing out the instabilities on the belt. The variables in their experiment are the fall height of the syrup (they actually used silicone oil) and the speed of the belt.

The result is a fanatastic panapoly of stitch-like patterns from a device they actually call a “fluid mechanical sewing machine”. Sticky Fingers Morris has even come up with a theory based on ad hoc arguments and numerical simulations to explain the nonlinear behavior. Surprisingly at least some of the behaviour can be explained by treating the thread like a rope being played out onto the belt.

All good fun and something to set the kids on during the holidays. But why no video fellas?

Ref: The Meandering Instability of a Viscous Thread

Comments are closed.