Interpretation of the Orientation of Ice Dendrites Growing from Supercooled Water

• Published in: Journal of Glaciology
• Main Author: Levi, Laura
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1970
• Subjects: Earth-Surface Processes; Journal of Glaciology
• Online Access: http://dx.doi.org/10.1017/s0022143000026836; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000026836

Abstract An interpretation is proposed of the phenomenon of splitting of ice dendrites growing from supercooled water and of their orientation at an angle α to the basal plane. Both phenomena are related to the instabilities which develop on the dendritic cap when the ratio V c /V a of the growth velocities in the direction of the c- and a -axes exceeds a certain limit. The different interface supercoolings, (δ T i ) a and (δ T i ) c at the tip and at the sides of the dendrite cap are considered. Although V c /V a increases with the bath supercooling Δ T it is found that V c ≪ V a for (δ T i ) c = (δ T i ) a through the whole range investigated (o < Δ T ≤ 18 deg). The increase of α with the concentration of solutes is also qualitatively explained. Considering the kinetic theory of the molecular growth mechanism, the results obtained for V c as a function of (δ T i ) c would indicate that most of the studied interval must correspond to the transitional regime of growth.