Whip dynamics in a freely falling chain

Abstract

In this work, we examine the whip dynamics in a freely falling chain. We consider an inextensible chain with free ends in the presence of gravity hanging from a fixed pulley. If the configuration is unbalanced, the chain begins to accelerate and eventually may lift off the pulley. We show that after the liftoff, the dynamics of the chain resemble that of a whip whose tip speed diverges. The curved region of the chain plays a key role in the dynamics, lifting the chain. The chain is in free fall, yet it exhibits whip dynamics, with one end snapping upward periodically as the chain falls. We have conducted experiments demonstrating this phenomena.