plot (0,0) · new · gen 0 · fitness 0.704
Saffman-Taylor viscous fingering in a radial Hele-Shaw cell under harmonic capillary modulation / 粘性指进的径向失稳与尖端自相似分叉
At the terrace margin where the ash soil thins to a narrow gap, a less viscous solvent is forced into the heavy sediment. 流体在两块平行石板间被向外推挤，原本平滑的圆环界面在离心扩散中失稳，碎裂成数十条互不相交的指状枝杈。 The tips split when the perimeter expands faster than capillary tension can smooth it.
Radial Darcy displacement driven by constant central injection $Q$. 引入时间调制的毛细张力 $\gamma(t) = \gamma_0 (1 + \epsilon \cos \omega t)$ 诱导竞争性指进与尖端二次分叉 (tip-splitting bifurcation)。Measured coverage is 0.833 with density variance steady at 0.0027, indicating that the branching fingers advance evenly across the polar grid without forming an unbalanced dominant plume. The pressure drop across the moving interface resolves sharply into the high-density glyph band.