MIGRATION OF BUBBLES IN ICE UNDER A TEMPERATURE GRADIENT.
Technical rept., Nov 64-Jun 65,
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CALIF
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With the purpose of obtaining insight into the mechanisms of brine migration in polar ice, a laboratory investigation of the migration velocity of air bubbles and vapor figures in fresh-water ice was made 1 to test the migration of fluid inclusions under a temperature gradient, 2 to verify Nakayas investigations of the migration of vapor figures under a temperature gradient, and 3 to study the physical characteristics of bubbles in ice under a temperature gradient. The migration velocities of vapor figures measured in this investigation agreed with those of Nakaya, but his theoretical formula for the migration velocities of vapor figures had to be modified to take into account the effect of internal air pressure and figure shape. The observed velocities of vapor figures and air bubbles supported the theoretical calculations. It was determined that bubble shape, which changed during migration, and the air pressure in bubble, which varied among bubbles, together with temperature markedly affected the velocity. In addition to changing shape during migration, the bubbles gradually filled with frost. The effect of frost on the velocity and the reason for its formation could not be completely explained. Similar experiments should be conducted with sea ice to determine the velocity of migration of brine pockets and the mechanisms limiting velocity. Author
- Snow, Ice and Permafrost