Vortex Ring Wake: 2D Point-Vortex Wake Model

The 3D flapping-wing sim shows a bird shedding vortex rings, but each ring moves on a scripted path — a fixed backward drift plus a hand-tuned sink rate — with no ring ever feeling the presence of another. This 2D companion asks a stricter question: what if every shed ring really is a pair of counter-rotating point vortices, and every one of them genuinely obeys the Biot-Savart law, mutually influencing every other vortex in the wake every frame? It does, and the payoff is real emergent behaviour — self-propagation speeds that fall out of the physics instead of being assumed, and later rings whose paths are measurably bent by the ones shed before them, the same many-body mechanism behind real vortex-ring leapfrogging.