Author(s): S. Clark; J. C. Doering
Linked Author(s):
Keywords: Frazil ice; Turbulence intensity; Particle size distributions
Abstract: In order to better understand the effect of turbulence intensity on frazil formation and evolution a series of experiments were undertaken at the Hydraulics Research & Testing Facility in the University of Manitoba using a counter-rotating flume. Five sets of bed plates ranging in roughness from roughened PVC to 20 mm gravel were used to generate turbulence in the flume Velocity measurements were made using a constant temperature anemometer with a conical hot film probe. The ability to rotate the flume walls at any given rate enabled the researchers to perform experiments where the average velocity was kept virtually constant, while the turbulence intensity increased with increasing bed roughness. Measurements of water and air temperature as well as digital images taken during ice formation were analyzed. It was found that although turbulence intensity seemed to have an effect on several of the key features of a supercooling curve, the relationships were not particularly strong The most significant finding is the mean diameter and standard deviation of the frazil disks seem to reach nearly constant values after several minutes of supercooling, and that these values were strongly affected by turbulence intensity. In addition, it is hypothesized that a power-law relationship could describe the variation of the mean diameter and standard deviation with time.
Year: 2006