(142cv) Suspension Properties At Finite Reynolds Number

The role of particle scale inertia in suspensions of neutrally buoyant monodisperse spherical particles is examined. Using numerical simulation via Lattice Boltzmann Method (LBM), trajectories and velocities of particles are calculated in simple shear flow. Based on relative pair velocities obtained for a range of Reynolds number and volume fractions, the variation of probability density for the vector, r, separating the center of the two spheres is calculated for a moving material point in r space. Shear induced self-diffusivities computed from the slope of the mean-square particle displacement and by integrating the corresponding velocity autocorrelation are also presented. To study the bulk stress of suspensions, the portraits of first and second normal stress difference are demonstrated in shear plane by sampling pair space, and are used along with the simulated microstructure of suspensions to explain the behavior of normal stress differences in suspensions at various levels of volume fraction and inertia.