Growth of an ice disk: dependence of critical thickness for disk instability on supercooling of water.
Growth of an ice disk: dependence of critical thickness for disk instability on supercooling of water.
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DOI：
10.1021/jp809808r
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发表时间：
2009-04
期刊：
影响因子：
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通讯作者：
E. Yokoyama;R. Sekerka;Y. Furukawa
中科院分区：
文献类型：
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作者：
E. Yokoyama;R. Sekerka;Y. Furukawa
通过对半径和厚度的生长速率的分析，研究了从过冷水中生长出的圆盘状冰晶的不对称图案。半径的增长由潜热的传输控制，并通过求解圆盘周围温度场的扩散方程来计算。厚度的增长是由台阶的产生和横向运动控制的，并表示为基面中心处过冷度的幂函数。当厚度达到临界值时，观察到相对于冰盘晶体的基面的对称性破坏;然后一个基面变得大于另一个，并且盘失去其圆柱形形状。随后，在不对称形状的较大基面的边缘处发生形态不稳定性（Shimada，W.; Furukawa，Y. 1997，B101，6171-6173）。我们表明，临界厚度与基面稳定生长的临界条件有关。两个基面之间的生长速率的差异是不对称形状的外观的可能机制。
The appearance of an asymmetrical pattern that occurs when a disk crystal of ice grows from supercooled water was studied by using an analysis of growth rates for radius and thickness. The growth of the radius is controlled by transport of latent heat and is calculated by solving the diffusion equation for the temperature field surrounding the disk. The growth of the thickness is governed by the generation and lateral motion of steps and is expressed as a power function of the supercooling at the center of a basal face. Symmetry breaking with respect to the basal face of an ice disk crystal is observed when the thickness reaches a critical value; then one basal face becomes larger than the other and the disk loses its cylindrical shape. Subsequently, morphological instability occurs at the edge of the larger basal face of the asymmetrical shape (Shimada, W.; Furukawa, Y. J. Phys. Chem. 1997, B101, 6171-6173). We show that the critical thickness is related to the critical condition for the stable growth of a basal face. A difference of growth rates between two basal faces is a possible mechanism for the appearance of the asymmetrical shape.