A two-way coupling scheme to model the effects of particle rotation on the rheological properties of a semidilute suspension

Fukui, Tsuguya; Kawaguchi, Misa; Morinishi, Koji

doi:10.1016/j.compfluid.2018.04.038

Cited by 18 publications

(40 citation statements)

References 46 publications

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“…It should be noted that microspheres themselves strongly influence near-wall microfluidics, as mentioned by Damiano et al 25 The relative viscosity determined from the relative wall shear stress was 1.475 6 0.291, which is compatible with that from Einstein's viscosity formula (1.503); however, the difference between the values increased with increase in the confinement. In fact, we previously reported that the relative viscosity for the confinement C = 0.0133 was 1.511 6 0.281, 18 which is closer to that from Einstein's viscosity formula. This is because Einstein's viscosity formula is based on the assumption that the confinement takes a limit of zero, in which case the suspended particles are infinitesimally small compared with the channel width.…”

Section: Resultssupporting

confidence: 74%

“…The grid resolution Dx, Dy was set to 1 mm in each direction; this provides good accuracy to consider suspension rheology. 18 The curved boundaries of the particles were described on a Cartesian grid by virtual flux method, 19,20 and a periodic boundary condition 18 was applied along the flow direction. One advantage of the virtual flux method is its superior spatial resolution (second-order accuracy) without adding an external force to describe an arbitrary body shape.…”

Section: Computational Modelsmentioning

confidence: 99%

“…Because the particles are assumed to be rigid and noncolloidal, their movements are simply expressed by Newton's second law of motion (equation 13) and by the equation of angular motion (equation 14) 18 F p = r…”

Section: Governing Equation For Fluid Part Of Simulationsmentioning

confidence: 99%

“…The external force vector F p = (F px , F py ) and the torque T p acting on each particle are solved numerically in terms of the hydrodynamic forces by a third-order Adams-Bashforth method. 18 Relative viscosity and power-law index…”

Section: Governing Equation For Fluid Part Of Simulationsmentioning

confidence: 99%

“…index values. The relative viscosity of a suspension was evaluated by the relative wall shear stress 18 in order to find its spatial variation…”

Section: Governing Equation For Fluid Part Of Simulationsmentioning

confidence: 99%

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Numerical study on the inertial effects of particles on the rheology of a suspension

Fukui

Kawaguchi

Morinishi

2019

Advances in Mechanical Engineering

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Einstein's viscosity formula is only applicable for dilute suspensions in which hydrodynamic interactions or inertial effects are sufficiently negligible. Therefore, the contribution of hydrodynamic interactions or the effects of inertia on the rheology of suspensions should be investigated. In order to evaluate the inertial effects of microscopic particles on the macroscopic rheology of a suspension, pressure-driven flow simulations with various confinements and Reynolds numbers were performed by a two-way coupling scheme. The results showed that the relative viscosity of the suspension decreases with increase in the particle size even when the concentration of the suspension remains the same. The results also indicated that the confinement should be less than 0.02 when applying Einstein's viscosity formula. Moreover, the relative viscosity of the suspension under a high Reynolds number condition increases because of outward particle migration, and the non-Newtonian property of the suspension changes from thixotropy to dilatancy. Suspension is a potential fluid because its macroscopic rheological properties are altered owing to suspended particles' behavior, that is, its microstructure. It can be stated that inertia is one of the promising factors to control suspension rheology.

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Section: Resultssupporting

confidence: 74%