When a chain flows up over the edge of a container and then falls to the ground below, it is observed that the top of the chain rises up above the container's edge. This is called a “chain fountain,” and is an entertaining and counterintuitive phenomenon. In this paper, the steady-state motion of the fountain is analyzed experimentally and theoretically. Measurements are given for the speeds and heights for three different chains and three different distances from the container to the floor. It is shown that the distance the chain rises above the container is proportional to the force from the container on the chain. A simple model is developed for how the chain interacts with the container, and shows that a link lifts-off from the container after rotating by a relatively small angle. The model's predictions agree very well with the measurements for the two ball-chains.
References
Neglecting the perturbative correction and making use of Eq. (14) leads to the simplified result quoted in the enhanced online abstract.
