Binary particle-particle interaction events in turbulence are simulated using the spectral elementbased DNS solver, Nek5000 and an immersed boundaries method. Particle-fluid coupling is achieved using the ghost-cell approach. Two periodic boxes of isotropic turbulence are obtained via linear forcing with Taylor microscale Reynolds numbers, ܴ݁Reλ = 29 and ܴ݁Reλ = 197. These have been selected to match those typical in the bulk and viscous sublayer regions of a ܴ݁Reₓ = 180 turbulent channel flow respectively. Both solid and fluid phase material and chemical properties are chosen to represent 100μm calcite particles in a 0.02݉m half-height channel flow. Simulations are initialised based on the most frequently occurring particle-particle collision events sampled from a four-way coupled DNS-LPT simulation. Particle interaction is modelled using interparticle forces based on DLVO theory and the hard sphere collision model.
Results indicate that particles in regions of increased turbulence are less likely to agglomerate, since their motion is dominated by the viscous and pressure forces on the particle, whereas in the bulk of the channel, forces transverse to streamwise motion allow pairs of particles travelling together to undergo agglomeration. Further variables of motion are monitored, such as angular velocity, in order to elucidate the effect of turbulence on a sphere’s rotational behaviour. It is to be determined in future work how the chemical and material properties of both phases affect these trajectories and potential for agglomeration
