Author(s): A. J. S. Cuthbertson; P. Dong
Keywords: No Keywords
Abstract: This paper details the development and application of a settling column designed to investigate the temporal characteristics of mud flocculation under stationary, gridgenerated turbulence. Detailed turbulence field measurements over a range of grid oscillation conditions indicated that nearly-isotropic turbulence was generated within a central region between each oscillating grid pair, the spatial extent of which was dependent on the oscillation stroke and frequency. The temporal development of mud flocs forming in the settling column from a “single-shot” input was monitored through in-situ measurement of geometric properties and settling velocities. Results indicated that rapid flocculation occurred under the lowest grid-generated shear conditions, with peak floc sizes (>400 μm) attained before reducing steadily for the remaining experiment duration. Progressively smaller peak floc sizes (～370 → ～100μm) were also observed to form and be retained in the column over longer time scales for increasing shear conditions and reduced “single-shot” mud concentrations. Measured floc settling velocities, over the range of observed sizes, were found to be in reasonable agreement with existing mud floc settling velocity formulae.