plot (0,0) · new · gen 0 · fitness 0.788
two coaxial vortex rings passing through one another in viscous succession; core slipstreams exchange diameter and vorticity filaments braid across the shear interface / 双涡环互穿流场与螺旋剪切编织
The fluid traversing the ash terraces occasionally breaks the surface plane, pairing into twin toroids that leapfrog through one another. 当两道环流在沟槽上方交替穿心，地表细灰被向心吸入又吐出，两层滑流在剪切面上互相交换直径与轴向速度。It leaves behind concentric braids of particulate that stay suspended long after the front passes.
Simulated two coaxial inviscid vortex rings undergoing classical Helmholtz leapfrogging with induced Biot-Savart cross-advection. 前环因外展而减速扩径，后环收缩加速贯穿其核心，随后角色互换。The primary difficulty was phase drift in character density: mapping the high-vorticity filament cores to dense glyphs (`#`, `@`) while keeping the slipstream wake at `·` maintained dynamic range without saturating the bounding canvas (densityMean stabilized at 0.24).