Search Menu
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information
Search Scholarly Publications

Title: Fractal dimension of cohesive sediment flocs at steady state under seven shear flow conditions

Abstract

The morphological properties of kaolin flocs were investigated in a Couette-flow experiment at the steady state under seven shear flow conditions (shear rates of 5.36, 9.17, 14, 24, 31, 41 and 53 s-1). These properties include a one-dimensional (1-D) fractal dimension (D1), a two-dimensional (2-D) fractal dimension (D2), a perimeter-based fractal dimension (Dpf) and an aspect ratio (AR). They were calculated based on the projected area (A), equivalent size, perimeter (P) and length (L) of the major axis of the floc determined through sample observation and an image analysis system. The parameter D2, which characterizes the relationship between the projected area and the length of the major axis using a power function, A ∝ LD2, increased from 1.73 ± 0.03, 1.72 ± 0.03, and 1.75 ± 0.04 in the low shear rate group (G = 5.36, 9.17, and 14 s-1) to 1.92 ± 0.03, 1.82 ± 0.02, 1.85 ± 0.02, and 1.81 ± 0.02 in the high shear rate group (24, 31, 41 and 53 s-1), respectively. The parameter D1 characterizes the relationship between the perimeter and length of the major axis by the function P ∝ LD1 and decreased from 1.52 ± 0.02, 1.48 ± 0.02, 1.55 ± 0.02,more » and 1.63 ± 0.02 in the low shear group (5.36, 9.17, 14 and 24 s-1) to 1.45 ± 0.02, 1.39 ± 0.02, and 1.39 ± 0.02 in the high shear group (31, 41 and 53 s-1), respectively. The results indicate that with increasing shear rates, the flocs become less elongated and that their boundary lines become tighter and more regular, caused by more breakages and possible restructurings of the flocs. The parameter Dpf, which is related to the perimeter and the projected area through the function , decreased as the shear rate increased almost linearly. The parameter AR, which is the ratio of the length of the major axis and equivalent diameter, decreased from 1.56, 1.59, 1.53 and 1.51 in the low shear rate group to 1.43, 1.47 and 1.48 in the high shear rate group. These changes in Dpf and AR show that the flocs become less convoluted and more symmetrical and that their boundaries become smoother and more regular in the high shear rate group than in the low shear rate group due to breakage and possible restructuring processes. To assess the effects of electrolyte and sediment concentration, 0.1 mol/L calcium chloride (CaCl2) and initial sediment concentration from 7.87 × 10-5 to 1.57 × 10-5 were used in this preliminary study. The addition of electrolyte and increasing sediment concentration could produce more symmetrical flocs with less convoluted and simpler boundaries. In addition, some new information on the temporal variation of the median size of the flocs during the flocculation process is presented.« less

Authors:
 [1];  [1];  [1];  [2];  [3]
+ Show Author Affiliations
  1. Beijing Normal University (China). College of Water Sciences.
  2. The Univ. of Tokyo, Kashiwa (Japan). Dept. of Natural Environmental Studies.
  3. Argonne National Lab. (ANL), Lemont, IL (United States)
Publication Date:
Research Org.:
Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1213671
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Accepted Manuscript
Journal Name:
Water (Basel)
Additional Journal Information:
Journal Name: Water (Basel); Journal Volume: 7; Journal Issue: 8; Journal ID: ISSN 2073-4441
Publisher:
MDPI
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; flocculation; fractal dimension; cohesive sediment; steady state; shear flow

Citation Formats

Zhu, Zhongfan, Yu, Jingshan, Wang, Hongrui, Dou, Jie, and Wang, Cheng. Fractal dimension of cohesive sediment flocs at steady state under seven shear flow conditions. United States: N. p., 2015. Web. doi:10.3390/w7084385.
Copy to clipboard
Zhu, Zhongfan, Yu, Jingshan, Wang, Hongrui, Dou, Jie, & Wang, Cheng. Fractal dimension of cohesive sediment flocs at steady state under seven shear flow conditions. United States. https://doi.org/10.3390/w7084385
Copy to clipboard
Zhu, Zhongfan, Yu, Jingshan, Wang, Hongrui, Dou, Jie, and Wang, Cheng. Wed . "Fractal dimension of cohesive sediment flocs at steady state under seven shear flow conditions". United States. https://doi.org/10.3390/w7084385. https://www.osti.gov/servlets/purl/1213671.
Copy to clipboard
@article{osti_1213671,
title = {Fractal dimension of cohesive sediment flocs at steady state under seven shear flow conditions},
author = {Zhu, Zhongfan and Yu, Jingshan and Wang, Hongrui and Dou, Jie and Wang, Cheng},
abstractNote = {The morphological properties of kaolin flocs were investigated in a Couette-flow experiment at the steady state under seven shear flow conditions (shear rates of 5.36, 9.17, 14, 24, 31, 41 and 53 s-1). These properties include a one-dimensional (1-D) fractal dimension (D1), a two-dimensional (2-D) fractal dimension (D2), a perimeter-based fractal dimension (Dpf) and an aspect ratio (AR). They were calculated based on the projected area (A), equivalent size, perimeter (P) and length (L) of the major axis of the floc determined through sample observation and an image analysis system. The parameter D2, which characterizes the relationship between the projected area and the length of the major axis using a power function, A ∝ LD2, increased from 1.73 ± 0.03, 1.72 ± 0.03, and 1.75 ± 0.04 in the low shear rate group (G = 5.36, 9.17, and 14 s-1) to 1.92 ± 0.03, 1.82 ± 0.02, 1.85 ± 0.02, and 1.81 ± 0.02 in the high shear rate group (24, 31, 41 and 53 s-1), respectively. The parameter D1 characterizes the relationship between the perimeter and length of the major axis by the function P ∝ LD1 and decreased from 1.52 ± 0.02, 1.48 ± 0.02, 1.55 ± 0.02, and 1.63 ± 0.02 in the low shear group (5.36, 9.17, 14 and 24 s-1) to 1.45 ± 0.02, 1.39 ± 0.02, and 1.39 ± 0.02 in the high shear group (31, 41 and 53 s-1), respectively. The results indicate that with increasing shear rates, the flocs become less elongated and that their boundary lines become tighter and more regular, caused by more breakages and possible restructurings of the flocs. The parameter Dpf, which is related to the perimeter and the projected area through the function , decreased as the shear rate increased almost linearly. The parameter AR, which is the ratio of the length of the major axis and equivalent diameter, decreased from 1.56, 1.59, 1.53 and 1.51 in the low shear rate group to 1.43, 1.47 and 1.48 in the high shear rate group. These changes in Dpf and AR show that the flocs become less convoluted and more symmetrical and that their boundaries become smoother and more regular in the high shear rate group than in the low shear rate group due to breakage and possible restructuring processes. To assess the effects of electrolyte and sediment concentration, 0.1 mol/L calcium chloride (CaCl2) and initial sediment concentration from 7.87 × 10-5 to 1.57 × 10-5 were used in this preliminary study. The addition of electrolyte and increasing sediment concentration could produce more symmetrical flocs with less convoluted and simpler boundaries. In addition, some new information on the temporal variation of the median size of the flocs during the flocculation process is presented.},
doi = {10.3390/w7084385},
journal = {Water (Basel)},
number = 8,
volume = 7,
place = {United States},
year = {Wed Aug 12 00:00:00 EDT 2015},
month = {Wed Aug 12 00:00:00 EDT 2015}
}
Copy to clipboard
Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
https://doi.org/10.3390/w7084385
Copyright Statement
Other availability
Search WorldCat Search WorldCat to find libraries that may hold this journal
Citation Metrics:
Cited by: 16 works
Citation information provided by
Web of Science
Save / Share:
Export Metadata
Save to My Library
You must Sign In or Create an Account in order to save documents to your library.

Works referenced in this record:

Understanding the role of restructuring in flocculation: The application of a population balance model
journal, January 2003

Population balance modeling of aggregation and breakage in turbulent Taylor–Couette flow
journal, March 2007

Effect of shear rate on aggregate size and structure in the process of aggregation and at steady state
journal, February 2013

Modelling the mechanical strength of fractal aggregates
journal, May 2001

  • Tang, S.; Ma, Y.; Shiu, C.
  • Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol. 180, Issue 1-2
  • DOI: 10.1016/S0927-7757(00)00743-3

Turbulence and the diffusive layers around small organisms
journal, November 1989

  • Lazier, J. R. N.; Mann, K. H.
  • Deep Sea Research Part A. Oceanographic Research Papers, Vol. 36, Issue 11
  • DOI: 10.1016/0198-0149(89)90068-X

A laboratory examination of floc characteristics with regard to turbulent shearing
journal, August 1999

Characterization of asphaltenes aggregation and fragmentation in a shear field
journal, July 2003

  • Rahmani, Nazmul H. G.; Masliyah, Jacob H.; Dabros, Tadeusz
  • AIChE Journal, Vol. 49, Issue 7
  • DOI: 10.1002/aic.690490705

A heuristic formula for turbulence-induced flocculation of cohesive sediment
journal, June 2006

  • Winterwerp, J. C.; Manning, A. J.; Martens, C.
  • Estuarine, Coastal and Shelf Science, Vol. 68, Issue 1-2
  • DOI: 10.1016/j.ecss.2006.02.003

Variable fractal dimension: A major control for floc structure and flocculation kinematics of suspended cohesive sediment
journal, January 2007

Shear-induced aggregation and breakup of polystyrene latex particles
journal, December 1992

Modeling flocculation processes of fine-grained particles using a size-resolved method: Comparison with published laboratory experiments
journal, November 2008

Fractal character of fracture surfaces of metals
journal, April 1984

  • Mandelbrot, Benoit B.; Passoja, Dann. E.; Paullay, Alvin J.
  • Nature, Vol. 308, Issue 5961
  • DOI: 10.1038/308721a0

Fractal dimensions of aggregates determined from steady-state size distributions
journal, December 1991

  • Jiang, Qing; Logan, Bruce E.
  • Environmental Science & Technology, Vol. 25, Issue 12
  • DOI: 10.1021/es00024a007

Fractal dimensions of aggregates formed in different fluid mechanical environments
journal, February 1995

Laminar and turbulent shear-induced flocculation of fractal aggregates
journal, May 1999

  • Flesch, Jürgen C.; Spicer, Patrick T.; Pratsinis, Sotiris E.
  • AIChE Journal, Vol. 45, Issue 5
  • DOI: 10.1002/aic.690450518

In situ measurement of particle aggregation and breakage kinetics in a concentrated suspension
journal, November 1992

Efficiency of different shear devices on flocculation
journal, February 2008

Modeling spatial distribution of floc size in turbulent processes using the quadrature method of moment and computational fluid dynamics
journal, January 2006

Dependence of initial cluster aggregation kinetics on shear rate for particles of different sizes under turbulence
journal, August 2009

  • Ehrl, Lyonel; Soos, Miroslav; Morbidelli, Massimo
  • AIChE Journal, Vol. 55, Issue 12
  • DOI: 10.1002/aic.11923

Effect of pipetting on mineral flocs
journal, February 1982

  • Gibbs, Ronald J.; Konwar, Lohit N.
  • Environmental Science & Technology, Vol. 16, Issue 2
  • DOI: 10.1021/es00096a012

Shear-induced flocculation: The evolution of floc structure and the shape of the size distribution at steady state
journal, May 1996

Simulating bacterial clustering around phytoplankton cells in a turbulent ocean
journal, January 1993

  • Bowen, James D.; Stolzenbach, Keith D.; Chisholm, Sallie W.
  • Limnology and Oceanography, Vol. 38, Issue 1
  • DOI: 10.4319/lo.1993.38.1.0036

Effect of flow field heterogeneity in coagulators on aggregate size and structure
journal, February 2010

  • Ehrl, Lyonel; Soos, Miroslav; Wu, Hua
  • AIChE Journal, Vol. 56, Issue 10
  • DOI: 10.1002/aic.12179

Image Analysis of Alum Coagulated Mineral Suspensions
journal, December 1996

Floc properties and settling velocity of San Jacinto estuary mud under variable shear and salinity conditions
journal, December 2010

A simple model for turbulence induced flocculation of cohesive sediment
journal, May 1998

The Effect of Impeller Type on Floc Size and Structure during Shear-Induced Flocculation
journal, December 1996

  • Spicer, Patrick T.; Keller, Wolfgang; Pratsinis, Sotiris E.
  • Journal of Colloid and Interface Science, Vol. 184, Issue 1
  • DOI: 10.1006/jcis.1996.0601

Experimental analysis of coagulation of particles under low-shear flow
journal, August 2005

Experimental Analysis of Floc Size Distribution and Hydrodynamics in a Jar-Test
journal, November 2001

Fractal geometry of particle aggregates generated in water and wastewater treatment processes
journal, November 1989

  • Li, Da Hong; Ganczarczyk, Jerzy
  • Environmental Science & Technology, Vol. 23, Issue 11
  • DOI: 10.1021/es00069a009

Flocculation model of cohesive sediment using variable fractal dimension
journal, January 2008

Evidence of Shear Rate Dependence on Restructuring and Breakup of Latex Aggregates
journal, April 2001

  • Selomulya, Cordelia; Amal, Rose; Bushell, Graeme
  • Journal of Colloid and Interface Science, Vol. 236, Issue 1
  • DOI: 10.1006/jcis.2000.7372

Aggregation and Breakup of Particles in a Shear Flow
journal, March 1997

  • Serra, Teresa; Colomer, Jordi; Casamitjana, Xavier
  • Journal of Colloid and Interface Science, Vol. 187, Issue 2
  • DOI: 10.1006/jcis.1996.4710

Aggregation kinetics of small particles in agitated vessels
journal, January 1997

Flocculation modelling: a review
journal, May 1999

Planktivorous feeding in calm and turbulent environments, with emphasis on copepods
journal, January 1995

Physical aspect of flocculation process—I: Fundamental treatise
journal, January 1979

Strength of aluminium hydroxide flocs
journal, September 1987

Structure of the Aggregates During the Process of Aggregation and Breakup Under a Shear Flow
journal, October 1998

  • Serra, Teresa; Casamitjana, Xavier
  • Journal of Colloid and Interface Science, Vol. 206, Issue 2
  • DOI: 10.1006/jcis.1998.5714

Effect of variable fractal dimension on the floc size distribution of suspended cohesive sediment
journal, September 2007

Flocculation of fine-grained sediments due to differential settling
journal, January 1993

  • Lick, Wilbert; Huang, Hening; Jepsen, Richard
  • Journal of Geophysical Research, Vol. 98, Issue C6
  • DOI: 10.1029/93JC00519

The effect of particle density on collisions between sinking particles: implications for particle aggregation in the ocean
journal, March 1994

  • Stolzenbach, Keith D.; Elimelech, Menachem
  • Deep Sea Research Part I: Oceanographic Research Papers, Vol. 41, Issue 3
  • DOI: 10.1016/0967-0637(94)90091-4

Growth Kinetics of Hydroxide Flocs
journal, June 1988

Laminar and turbulent shear-induced flocculation of fractal aggregates
journal, May 1999

  • Flesch, Jürgen C.; Spicer, Patrick T.; Pratsinis, Sotiris E.
  • AIChE Journal, Vol. 45, Issue 5
  • DOI: 10.1002/aic.690450518

The Effect of Impeller Type on Floc Size and Structure during Shear-Induced Flocculation
journal, December 1996

  • Spicer, Patrick T.; Keller, Wolfgang; Pratsinis, Sotiris E.
  • Journal of Colloid and Interface Science, Vol. 184, Issue 1
  • DOI: 10.1006/jcis.1996.0601

Aggregation and Breakup of Particles in a Shear Flow
journal, March 1997

  • Serra, Teresa; Colomer, Jordi; Casamitjana, Xavier
  • Journal of Colloid and Interface Science, Vol. 187, Issue 2
  • DOI: 10.1006/jcis.1996.4710

Shear-induced flocculation: The evolution of floc structure and the shape of the size distribution at steady state
journal, May 1996

Effect of variable fractal dimension on the floc size distribution of suspended cohesive sediment
journal, September 2007

Effect of shear rate on aggregate size and structure in the process of aggregation and at steady state
journal, February 2013

Characterizing flocculation under heterogeneous turbulence
journal, August 2003

Floc morphology and size distributions of cohesive sediment in steady-state flow
journal, June 2003

On the flocculation and settling velocity of estuarine mud
journal, June 2002

Effects of floc strength on viscosity and deposition of cohesive sediment suspensions
journal, October 1999

Aggregation and Disaggregation of Fine-Grained Lake Sediments
journal, January 1988

Effect of pipetting on mineral flocs
journal, February 1982

  • Gibbs, Ronald J.; Konwar, Lohit N.
  • Environmental Science & Technology, Vol. 16, Issue 2
  • DOI: 10.1021/es00096a012

The flocculation of fine-grained sediments in estuarine waters
journal, January 1989

  • Burban, Pierre-Yves; Lick, Wilbert; Lick, James
  • Journal of Geophysical Research, Vol. 94, Issue C6
  • DOI: 10.1029/jc094ic06p08323

Experimental Analysis of Floc Size Distribution and Hydrodynamics in a Jar-Test
journal, November 2001

Planktivorous feeding in calm and turbulent environments, with emphasis on copepods
journal, January 1995

    Sort by:
    [ × clear filter / sort ]

    Works referencing / citing this record:

    Size, orientation, and strength of Na-montmorillonite flocs flowing in a laminar shear flow
    journal, July 2019

    In situ polymer flocculation and growth in Taylor–Couette flows
    journal, January 2018

    • Metaxas, Athena; Wilkinson, Nikolas; Raethke, Ellie
    • Soft Matter, Vol. 14, Issue 42
    • DOI: 10.1039/c8sm01694a

    Dynamics of Sediment Transport and Erosion-Deposition Patterns in the Locality of a Detached Low-Crested Breakwater on a Cohesive Coast
    journal, August 2019

    • Fitri, Arniza; Hashim, Roslan; Abolfathi, Soroush
    • Water, Vol. 11, Issue 8
    • DOI: 10.3390/w11081721

    Dynamics of Sediment Transport and Erosion-Deposition Patterns in the Locality of a Detached Low-Crested Breakwater on a Cohesive Coast
    journal, August 2019

    • Fitri, Arniza; Hashim, Roslan; Abolfathi, Soroush
    • Water, Vol. 11, Issue 8
    • DOI: 10.3390/w11081721
      Sort by:
      [ × clear filter / sort ]

      Similar Records in DOE PAGES and OSTI.GOV collections: