N point vortices in 2D ideal flow. Governed by Hamiltonian mechanics: ẋᵢ = −∂H/∂yᵢ, ẏᵢ = ∂H/∂xᵢ where H = −1/4π Σᵢ≠ⱼ ΓᵢΓⱼ ln|rᵢⱼ|.
Click canvas to add positive vortex (Γ=+1), Shift+click for negative (Γ=−1). Conservation laws: total circulation Γ_total, linear impulse P, angular impulse L, energy H are all conserved.