Anomalous Convective Flows Carve Pinnacles and Scallops in Melting Ice
Anomalous Convective Flows Carve Pinnacles and Scallops in Melting Ice
复制标题
异常对流在融化的冰中雕刻出尖峰和扇贝
DOI：
10.1103/physrevlett.128.044502
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发表时间：
2022
影响因子：
8.6
通讯作者：
Ristroph, Leif
中科院分区：
文献类型：
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作者：
Weady, Scott;Tong, Joshua;Zidovska, Alexandra;Ristroph, Leif
我们报道了冰在冰冷的淡水中悬浮并受到融化过程中产生的自然对流的影响的形状动力学。实验揭示了增加远场温度的形状主题：在低温下指向下方的尖顶，在和之间的中间温度下的扇形波，以及在较高温度下向上指向的尖顶。相场模拟再现了这些形态，它们与液态水的反常密度-温度分布密切相关。边界层流动产生尖峰，尖峰随着尖端曲率的加速增长而变得尖锐，而扇贝则是由于逆流卷曲形成涡阵而产生的Kelvin-Helmholtz类不稳定。通过将水密度异常背后的分子尺度效应与印记表面的大尺度流动联系起来，这些结果表明，融化的冰的形态是环境温度的敏感指标。
We report on the shape dynamics of ice suspended in cold fresh water and subject to the natural convective flows generated during melting. Experiments reveal shape motifs for increasing far-field temperature: Sharp pinnacles directed downward at low temperatures, scalloped waves for intermediate temperatures betweenand, and upward pointing pinnacles at higher temperatures. Phase-field simulations reproduce these morphologies, which are closely linked to the anomalous density-temperature profile of liquid water. Boundary layer flows yield pinnacles that sharpen with accelerating growth of tip curvature while scallops emerge from a Kelvin-Helmholtz–like instability caused by counterflowing currents that roll up to form vortex arrays. By linking the molecular-scale effects underlying water’s density anomaly to the macroscale flows that imprint the surface, these results show that the morphology of melted ice is a sensitive indicator of ambient temperature.