Rheology of Hyperconcentrations

Rheological study of mudflows at Lianyungang in China

“…The simplest theoretical model for yield stress fluid is the Bingham model, which exhibits a linear stress-strain relationship at shear stress in excess of the yield stress. In most cases, fitting the experimental data with satisfactory accuracy is not good over the low range of shear rates by this model (Julien & Lan, 1991;Kessel & Blom, 1998;Toorman, 1994;Coussot et al, 1996;Maciel et al, 2009). Kessel and Blom (1998) However, it can be found in Fig.…”

“…Although there is a debate in the literature on the existence of a "true" yield stress, in the present study the existence of the yield stress is assumed for natural mud. In practice, it is difficult to ascribe a value to the yield stress in that both the different rheological model selected and the flow curve segmented for extrapolation lead to a wide distribution in the published data of yield stress (James et al, 1987;Julien & Lan, 1991;Chhabra, 2006). Therefore, the yield stress obtained by different models should not be directly compared with each other and the extrapolation beyond the range of experimental conditions must be treated with caution.…”

A laboratory study of rheological properties of mudflows in Hangzhou Bay, China

“…It has been found in the literature that the above models sometimes cannot fit measured flow curves with satisfactory accuracy in the region of low shear rate (Julien and Lan, 1991;Toorman, 1994;etc.). In particular, Toorman (1994) examined the following Worrall-Tuliani model proposed by Worrall and Tuliani (1964) for clay suspensions (Malcherek et al, 1996;Mayne et al, 2002) ( )…”

“…For example, James et al (1987) used Casson's equation (Casson,1957) to define a nonlinear yield stress at zero shear rate and used Bingham model to determine the Bingham yield stress by an extrapolation of the linear segment of a flow curve at higher shear rate. Julien and Lan (1991) used a quadratic model to determine the yield stress in their paper. In general, yield stresses obtained by different rheological models should not be directly compared with each other.…”

Dependence of Sediment Suspension Viscosity on Solid Concentration: A Simple General Equation

“…Understanding cohesive sediment transport is important for engineering projects related to dredging operations of navigation channels, morphological changes of shorelines and water quality control in estuarine and coastal areas [2][3][4][5][6]. Transport of cohesive sediment occurs both in the water column and in the near-bed water layer.…”