Simplified Physically Based Model for Estimating Effective Floc Density
Publication: Journal of Hydraulic Engineering
Volume 137, Issue 8
Abstract
This paper applies dimensional analysis to propose an alternative model for estimating the effective density of flocs (). The model takes into account the effective density of the primary particles, in addition to the sizes of the floc and primary particles, and does not consider the concept of self-similarity. The model contains three dimensionless products and two empirical parameters ( and ), which were calibrated by using data available in the literature. Values of and were obtained. The average value of the primary particle size () for the data used in the analysis, inferred from the new model, was found to vary from 0.05 μm to 100 μm with a mean value of 2.5 μm. Good comparisons were obtained in comparing the estimated floc-settling velocity on the basis of the proposed model for effective floc density with the measured value.
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References
Alldredge, A. L., and Gotschalk, C. (1988). “In situ settling behavior of marine snow.” Limnol. Oceanogr., 33(3), 339–351.
Bache, D. H. (2004). “Floc rupture and turbulence: A framework for analysis.” Chem. Eng. Sci., 59(12), 2521–2534.
Camenen, B. (2008). “Settling velocity of sediments at high concentrations.” Sediment and Ecohydraulics: INTERCOH 2005, T. Kusuda, H. Yamanishi, J. Spearman and J. Z. Gailani, eds., Elsevier, London, 211–226.
Curran, K. J., et al. (2007). “Settling velocity, effective density, and mass composition of suspended sediment in a coastal bottom boundary layer, Gulf of Lions, France.” Cont. Shelf Res., 27(10-11), 1408–1421.
Dankers, P. J. T., Winterwerp, J. C., and Van Kesteren, W. G. M. (2007). “A preliminary study on the hindered settling of kaolinite flocs.” Estuarine and Coastal Fine Sediment Dynamics: INTERCOH 2003, J. P.-Y. Maa, L. P. Sanford, and D. H. Schoellhamer, eds., Elsevier, London, 227–241.
Diercks, A. R., and Asper, V. L. (1997). “In situ settling speeds of marine snow aggregates below the mixed layer: Black Sea and Gulf of Mexico.” Deep Sea Res. Part I, 44(3), 385–398.
Droppo, I. G. (2001). “Rethinking what constitutes suspended sediment.” Hydrol. Processes, 15(9), 1551–1564.
Droppo, I. G., Leppard, G. G., Liss, S. N., and Milligan, T. G. (2005). “Opportunities, needs, and strategic direction for research on flocculation in natural and engineered systems.” Flocculation in natural and engineered environmental systems, I. G. Droppo, G. G. Leppard, S. N. Liss, and T. G. Milligan, eds., CRC Press, London, 407–421.
Hughes, S. A. (1993). Physical models and laboratory techniques in coastal engineering, World Scientific, Singapore.
Khelifa, A., and Hill, P. S. (2006). “Models for effective density and settling velocity of flocs.” J. Hydraul. Res., 44(3), 390–401.
Kranenburg, C. (1994). “The fractal structure of cohesive sediment aggregates.” Estuarine Coastal Shelf Sci., 39(6), 451–460.
Maggi, F. (2005). “Flocculation dynamics of cohesive sediment.” Ph.D. thesis, Delft Univ. of Technology, Netherlands.
Petticrew, E. L. (2005). “The composie nature of suspended and gravel stored fine sediment in stream: A case study of O’Ne-eil Creek, British Columbia, Canda.” Flocculation in natural and engineered environmental systems, I. G. Droppo, G. G. Leppard, S. N. Liss, and T. G. Milligan, eds., CRC Press, London, 1–21.
Tambo, N., and Watanabe, Y. (1979). “Physical characteristics of flocs—I. The floc density function and aluminium floc.” Water Res., 13(5), 409–419.
Thorn, M. F. C. (1982). “Physical process of siltation in tidal channels.” Hydraulic modelling in maritime engineering: Proc., conf. organized by the Institution of Civil Engineers, Thomas Telford, London, 65–73.
van Rijn, L. C. (1993). Principles of sediment transport in rivers, estuaries and coastal seas, Aqua Publications, Netherlands.
Williams, N. D., Walling, D. E., and Leeks, G. J. L. (2008). “An analysis of the factors contributing to the settling potential of fine fluvial sediment.” Hydrol. Processes, 22(20), 4153–4162.
Winterwerp, J. C. (1999). “On the dynamics of high-concentrated mud suspensions.” Ph.D. thesis, Delft Univ. of Technology, Netherlands.
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© 2011 American Society of Civil Engineers.
History
Received: Sep 2, 2009
Accepted: Oct 28, 2010
Published online: Jan 24, 2011
Published in print: Aug 1, 2011
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