Rheology of dense suspensions of non-colloidal spheres in yield-stress fluids

2015 ◽  
Vol 776 ◽  
Author(s):  
Simon Dagois-Bohy ◽  
Sarah Hormozi ◽  
Élisabeth Guazzelli ◽  
Olivier Pouliquen
Keyword(s):  
Shear Stress ◽  
Rheological Properties ◽  
Normal Stress ◽  
Yield Stress ◽  
Rheological Measurements ◽  
Model Based ◽  
Colloidal Spheres ◽  
Yield Stress Fluids ◽  
Dense Suspensions ◽  
Scaling Arguments

Pressure-imposed rheometry is used to study the rheological properties of suspensions of non-colloidal spheres in yield-stress fluids. Accurate measurements for both the shear stress and the particle normal stress are obtained in the dense regime. The rheological measurements are favourably compared with a model based on scaling arguments and homogenisation methods.

An attempt to categorize yield stress fluid behaviour

2009 ◽  
Vol 367 (1909) ◽  
pp. 5139-5155 ◽  
Author(s):  
Peder Moller ◽  
Abdoulaye Fall ◽  
Vijayakumar Chikkadi ◽  
Didi Derks ◽  
Daniel Bonn
Keyword(s):  
Shear Stress ◽  
Experimental Determination ◽  
Yield Stress ◽  
Shear Banding ◽  
Ongoing Debate ◽  
Yield Stress Fluids ◽  
Dense Suspensions ◽  
Experimental Protocols ◽  
Fluid Behaviour

We propose a new view on yield stress materials. Dense suspensions and many other materials have a yield stress—they flow only if a large enough shear stress is exerted on them. There has been an ongoing debate in the literature on whether true yield stress fluids exist, and even whether the concept is useful. This is mainly due to the experimental difficulties in determining the yield stress. We show that most if not all of these difficulties disappear when a clear distinction is made between two types of yield stress fluids: thixotropic and simple ones. For the former, adequate experimental protocols need to be employed that take into account the time evolution of these materials: ageing and shear rejuvenation. This solves the problem of experimental determination of the yield stress. Also, we show that true yield stress materials indeed exist, and in addition, we account for shear banding that is generically observed in yield stress fluids.

scholarly journals Temperature Effects on Rheological Properties of Fresh Thickened Copper Tailings that Contain Cement

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Yong Wang ◽  
Aixiang Wu ◽  
Zhuen Ruan ◽  
Hongjiang Wang ◽  
Yiming Wang ◽  
...  
Keyword(s):  
Shear Stress ◽  
Pressure Drop ◽  
Rheological Properties ◽  
Yield Stress ◽  
Apparent Viscosity ◽  
Temperature Effects ◽  
Underground Mining ◽  
Effect Of Temperature ◽  
Large Temperature ◽  
Pipeline Transport

Cemented paste backfill (CPB) is an economic and environmental friendly technique applied in underground mining for supporting surrounding rock and replacing the pillar. However, little is known about the temperature effects on CPB in mines having a large temperature fluctuation. The main purpose of this research was to investigate the effect of temperature change on the rheological properties (e.g., shear stress and apparent viscosity) of CPB with copper mine tailings. Specifically, a series of rheological tests were conducted on 6 CPB samples using a Brookfield R/S+ Rheometer under various temperatures (2°C, 10°C, 20°C, 30°C, 40°C, and 60°C). Our results showed that both shear stress and apparent viscosity of these tailing samples increased with temperature rising from 2 to 60°C. Likewise, temperature has a significant impact on the Bingham yield stress of thickened tailings. The yield stress decreased from 122 Pa (2°C) to 112 Pa (20°C) and then increased to 152 Pa (60°C). Moreover, the pipeline transport pressure drop of CPB at various temperatures was calculated, illustrating an obvious effect on the paste pipeline transport. Compared with 20°C, the pressure drop under 2°C and 60°C increased by 11% and 22%, respectively. The results of this study indicate that the temperature plays an essential role in determining rheological properties of CPB and its engineering application in mines particularly with naturally fluctuating temperatures.

scholarly journals Microstructure and thickening of dense suspensions under extensional and shear flows

2017 ◽  
Vol 825 ◽  
Author(s):  
Ryohei Seto ◽  
Giulio G. Giusteri ◽  
Antonio Martiniello
Keyword(s):  
Numerical Simulation ◽  
Rheological Properties ◽  
Normal Stress ◽  
Shear Flows ◽  
Shear Thickening ◽  
Newtonian Fluids ◽  
Flow Type ◽  
Dense Suspensions ◽  
Strong Shear ◽  
Normal Stress Differences

Dense suspensions are non-Newtonian fluids that exhibit strong shear thickening and normal stress differences. Using numerical simulation of extensional and shear flows, we investigate how rheological properties are determined by the microstructure that is built under flows and by the interactions between particles. By imposing extensional and shear flows, we can assess the degree of flow-type dependence in regimes below and above thickening. Even when the flow-type dependence is hindered, non-dissipative responses, such as normal stress differences, are present and characterise the non-Newtonian behaviour of dense suspensions.

scholarly journals Rheological properties of living cytoplasm: endoplasm of Physarum plasmodium.

1983 ◽  
Vol 97 (4) ◽  
pp. 1089-1097 ◽  
Author(s):  
M Sato ◽  
T Z Wong ◽  
R D Allen
Keyword(s):  
Shear Stress ◽  
Rheological Properties ◽  
Yield Stress ◽  
Viscoelastic Fluid ◽  
Physarum Polycephalum ◽  
Complex Function ◽  
Homogeneous Material ◽  
Magnetic Forces ◽  
Magnetic Sphere ◽  
Double Chamber

Magnetic sphere viscoelastometry, video microscopy, and the Kamiya double chamber method (Kamiya, N., 1940, Science [Wash. DC], 92:462-463.) have been combined in an optical and rheological investigation of the living endoplasm of Physarum polycephalum. The rheological properties examined were yield stress, viscosity (as a function of shear), and elasticity. These parameters were evaluated in directions perpendicular; (X) and parallel (Y) to the plasmodial vein. Known magnetic forces were used for measurements in the X direction, while the falling ball technique was used in the Y direction (Cygan, D.A., and B. Caswell, 1971, Trans. Soc. Rheol. 15:663-683; MacLean-Fletcher, S.D., and T.D. Pollard, 1980, J. Cell Biol., 85:414-428). Approximate yield stresses were calculated in the X and Y directions of 0.58 and 1.05 dyn/cm2, respectively. Apparent viscosities measured in the two directions (eta x and eta y) were found to fluctuate with time. The fluctuations in eta x and eta y were shown, statistically, to occur independently of each other. Frequency correlation with dynamoplasmograms indicated that these fluctuations probably occur independently of the streaming cycle. Viscosity was found to be a complex function of shear, indicating that the endoplasm is non-Newtonian. Plots of shear stress vs. rate of shear both parallel and perpendicular to the vein, showed that endoplasm is not a shear thinning material. These experiments have shown that living endoplasm of Physarum is an anisotropic viscoelastic fluid with a yield stress. The endoplasm appears not to be a homogeneous material, but to be composed of heterogeneous domains.

Dynamic and shear stress rheological properties of guar galactomannans and its hydrolyzed derivatives

2015 ◽  
Vol 72 ◽  
pp. 687-691 ◽  
Author(s):  
Majid Hussain ◽  
Serafim Bakalis ◽  
Ourania Gouseti ◽  
Tahir Zahoor ◽  
Faqir Muhammad Anjum ◽  
...  
Keyword(s):  
Shear Stress ◽  
Rheological Properties
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