Modeling of flow of particles in a non-Newtonian fluid using lattice Boltzmann method

To predict correctly the castings process of self compacting concrete a numerical model capable of simulating flow patterns at the structural scale and at the same time the impact of the varying volume fraction of aggregates and other phenomena at the scale of aggregates on the flow evolution is necessary.

In this contribution, the model at the scale of aggregates is introduced. The conventional lattice Boltzmann method for fluid flow is enriched with the immersed boundary method with direct forcing to simulate the flow of rigid particles in a non- Newtonian liquid. Basic ingredients of the model are presented and discussed with the emphasis on a newly developed algorithm for the dynamics of particles whose interactions strongly depend on velocities of particles.

The application of the model is demonstrated by a parametric study with varying volume fractions of aggregates and speed of shearing used for computation of effective viscosities. It is shown that the presented model based on well established methods and without any artificial parameters, numerical tricks or modifications provides an efficient tool that can be applied to a range of engineering problems on different length-scales yielding results matching favorably theoretical or experimental findings.