The Modeling for Coupled Elastoplastic Geomechanics and Two-Phase Flow With Capillary Hysteresis in Porous Media

We study new constitutive relations employing the fundamental theory of elastoplasticity for two coupled irreversible processes: elastoplastic geomechanics and two-phase flow with capillary hysteresis. The fluid content is additively decomposed into elastic and plastic parts with infinitesimal transformation assumed. Specifically, the plastic fluid content, i.e., the total residual (or irrecoverable) saturation, is also additively decomposed into constituents due to the two irreversible processes: the geomechanical plasticity and the capillary hysteresis. The additive decomposition of the plastic fluid content facilitates combining the existing two individual simulators easily, for example, by using the fixed-stress sequential method. For pore pressure of the fluid in multi-phase which is coupled with the geomechanics, the equivalent pore pressure is employed, which yields the well-posedness of coupled multi-phase flow and geomechanics, regardless of the capillarity. We perform an energy analysis to show the well-posedness of the proposed model. And numerical examples demonstrate stable solutions for cyclic imbibition/drainage and loading/unloading processes. Employing the van Genuchten and the Drucker Prager models for capillary and the plasticity, respectively, we show the robustness of the model for capillary hysteresis in multiphase flow and elastoplastic geomechanics.

Modelling vertical concentration distributions of solids suspended in turbulent visco-plastic fluid

Vertical concentration distributions of solids conveyed in Newtonian fluids can be modelled using Rouse-Schmidt type distributions. Observations of solids conveyed in turbulent low Reynolds number visco-plastic carriers, suggest that solids are more readily suspended than their Newtonian counterparts, producing higher concentrations in the centre of the pipe. A Newtonian concentration profile model was adapted to include typical turbulent viscosity distributions within the pipe and particle motion calculated using non-Newtonian sheared settling. Predictions from this and the unmodified model, using the same wall viscosity, are compared with the chord averaged profile extracted from tomographic data obtained using a 50 mm horizontal pipe.

Experimental Investigation on Rheological Properties of Water Based Novel Ternary Hybrid Nanofluids

This study presents the rheological characterization of deionised water dispersed with two different ternary-hybrid nanoparticles namely, GO-TiO2-Ag and rGO-TiO2-Ag. The stability of 0.05 wt% nanofluid samples are serially diluted by 10 fold in 5 levels is determined using zeta potential measurements. The non-linear viscoelastic measurements at temperatures ranging from 25oC to 50oC reveal that the graphene based ternary hybrid nanoparticle nanofluids exhibit Newtonian behaviour at higher concentrations. However, it displays shear thinning or pseudo-plastic fluid characteristics at lower concentration, suggesting a potential influence of nanoparticle aggregation on the viscosity. The experimental results are found to be in good agreement with the existing water based viscosity models. In addition, the effect due to shear stress, angular sweep, frequency sweep and damping factor ratio is also plotted.

Experimental Investigation on Rheological Properties of Water Based Novel Ternary Hybrid Nanofluids

This study presents the rheological characterization of deionised water dispersed with two different ternary-hybrid nanoparticles namely, GO-TiO2-Ag and rGO-TiO2-Ag. The stability of 0.05 wt% nanofluid samples are serially diluted by 10 fold in 5 levels is determined using zeta potential measurements. The non-linear viscoelastic measurements at temperatures ranging from 25oC to 50oC reveal that the graphene based ternary hybrid nanoparticle nanofluids exhibit Newtonian behaviour at higher concentrations. However, it displays shear thinning or pseudo-plastic fluid characteristics at lower concentration, suggesting a potential influence of nanoparticle aggregation on the viscosity. The experimental results are found to be in good agreement with the existing water based viscosity models. In addition, the effect due to shear stress, angular sweep, frequency sweep and damping factor ratio is also plotted.

Experimental Investigation on Rheological Properties of Water Based Novel Ternary Hybrid Nanofluids

This study presents the rheological characterization of deionised water dispersed with two different ternary-hybrid nanoparticles namely, GO-TiO2-Ag and rGO-TiO2-Ag. The stability of 0.05 wt% nanofluid samples are serially diluted by 10 fold in 5 levels is determined using zeta potential measurements. The non-linear viscoelastic measurements at temperatures ranging from 25oC to 50oC reveal that the graphene based ternary hybrid nanoparticle nanofluids exhibit Newtonian behaviour at higher concentrations. However, it displays shear thinning or pseudo-plastic fluid characteristics at lower concentration, suggesting a potential influence of nanoparticle aggregation on the viscosity. The experimental results are found to be in good agreement with the existing water based viscosity models. In addition, the effect due to shear stress, angular sweep, frequency sweep and damping factor ratio is also plotted.

Numerical exploration of thin film flow of MHD pseudo-plastic fluid in fractional space: Utilization of fractional calculus approach

In this article, thin film flow of non-Newtonian pseudo-plastic fluid is investigated on a vertical wall through homotopy-based scheme along with fractional calculus. Three cases were examined after considering (i) partial fractional differential equation (PFDE) by altering first-order derivative to fractional derivative in the interval (0, 1), (ii) PFDE by altering second-order derivative to fractional derivative in the interval (1, 2), and (iii) fully FDE by altering first-order derivative to fractional derivative in (0, 1) and second-order derivative to fractional derivative in (1, 2). Different physical quantities such as the velocity profile and volume flux were computed and analyzed. Validity of obtained results was checked by finding residuals. Moreover, consequence of different parameters on the velocity were also explored in fractional space.