Laboratory Experiments on Frazil-Size Characteristics in a Counterrotating Flume

In an attempt to increase the fundamental understanding of the formation and evolution of frazil ice, laboratory experiments have been conducted in a counterrotating flume at the Hydraulics Research and Testing Facility, University of Manitoba. A highprecision thermometer and recently improved digital image processing system were used to acquire data from these experiments, which will hopefully aid in the development of numerical models. The image processing system is described, and results from a series of experiments are presented. The effects of air temperature, water velocity, and bottom roughness on the formation of frazil ice are discussed. A lognormal distribution appears to provide a reasonable fit to the observed frazil particle size distributions.