Suspension properties at finite Reynolds number from simulated shear flow

This work examines the role of particle-scale inertia in a monodisperse suspension of non-Brownian and neutrally buoyant spherical particles subjected to simple-shear flow. The dimensionless parameters governing the problem are the solid-volume fraction ϕ and the Reynolds number defined Re=ργ̇a2∕μ, where a is the sphere radius, γ̇ is the shear rate, and μ and ρ are the viscosity and density of the fluid, respectively. Using numerical simulations in a wall-bounded domain via the lattice-Boltzmann method, the bulk rheological properties of relative viscosity, normal stress differences, and particle pressure are reported for 0.01⩽Re<5 and 0.05⩽ϕ⩽0.3. The anisotropy in microstructure at finite Re is studied through the pair distribution function g(r). Also presented are the probability density functions of particle velocity fluctuations in gradient and vorticity directions. Comparisons to low Reynolds number theory and simulations are provided wherever possible.