Open AccessOn the Kaolinite Floc Size at the Steady State of Flocculation in a Turbulent Flow
Author(s) -
Zhongfan Zhu,
Hongrui Wang,
Jingshan Yu,
Jie Dou
Publication year - 2016
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0148895
Subject(s) - flocculation , shear (geology) , particle size , shear flow , turbulence , shear rate , flow conditions , materials science , grain size , geotechnical engineering , mineralogy , chemistry , geology , rheology , environmental science , mechanics , flow (mathematics) , environmental engineering , physics , composite material
The flocculation of cohesive fine-grained sediment plays an important role in the transport characteristics of pollutants and nutrients absorbed on the surface of sediment in estuarine and coastal waters through the complex processes of sediment transport, deposition, resuspension and consolidation. Many laboratory experiments have been carried out to investigate the influence of different flow shear conditions on the floc size at the steady state of flocculation in the shear flow. Most of these experiments reported that the floc size decreases with increasing shear stresses and used a power law to express this dependence. In this study, we performed a Couette-flow experiment to measure the size of the kaolinite floc through sampling observation and an image analysis system at the steady state of flocculation under six flow shear conditions. The results show that the negative correlation of the floc size on the flow shear occurs only at high shear conditions, whereas at low shear conditions, the floc size increases with increasing turbulent shear stresses regardless of electrolyte conditions. Increasing electrolyte conditions and the initial particle concentration could lead to a larger steady-state floc size.