Jellyfish Bell Contraction: Vortex-Ring Thrust

This simulator models medusa jet propulsion from first principles: a bell of a given diameter contracts fast and relaxes slowly on a tunable duty cycle, the rate of change of its enclosed volume sets an ejected flow rate through the sub-umbrella orifice, and that flow's momentum flux produces a real thrust force balanced against quadratic drag to give a swim speed. Each contraction sheds a visible vortex ring — the same coherent wake structure biomechanics research has documented as the mechanism behind efficient jellyfish and squid propulsion — while live readouts track bell diameter, jet velocity, thrust and swim speed as you adjust frequency, duty cycle, bell size and drag.