A laboratory study of frazil evolution in a counter-rotating flume

Abstract

A series of experiments was carried out using a counter-rotating flume that is housed in a computer-controlled cold room. A digital image process system (DIPS) was used to observe frazil ice processes. In particular, the effects of air temperature and flow velocity on the supercooling and frazil ice processes were examined. The super cooling process was found to be strongly related to air temperature and water depth, but only weakly related to water velocity. The water velocity has a strong influence on frazil evolution, frazil size, and number of the particles, however. The measured frazil size distribution by volume was found to be reasonably well approximated by a log-normal distribution. Frazil growth continues in number and size during supercooling and appears to reach a stable state at the end of the principal period of supercooling. All characteristic parameters of the supercooling processes and frazil size distribution were found to be related to the Reynolds number, an index of the intensity of flow turbulence. This information can be used in the development of models of frazil ice dynamics.Key words: supercooling, frazil ice, distribution, flow velocity, air temperature, turbulence.