The impact of the collision model employed when simulating fully resolved particles interacting in a fluid is investigated in the present study. We are using for this purpose a p seudo-spectral in compressib le Direct Numerical Simulation (DNS) code based on the Navier-Stokes equation as well as a Lattice-Boltzmann Method (LBM), developed in our group and coupled with the direct-forcing Immersed Boundary Method (IBM) to describe the particles.

Most of the corresponding literature assumes that the collision model does not have a significant impact on the flow field. Additionally, the impact of the collision model on the particle trajectories has not been analyzed in a systematic manner. Thus, by using the DNS solver, four different collision models (velocity barrier, repulsive potential force, lubrication barrier and hard-sphere model) have been employed in order to examine consequences for particle behavior and turbulence structure. It was found that the particle motion and turbulence statistics are qualitatively similar for all models. However, noticeable quantitative differences appear concerning the turbulent dissipation rate.

In the LBM section two different types of repulsive-force collision model are selected and their effect on a 2D fluid-particle interaction is investigated. Furthermore, other factors affecting performance of the LB-IBM solver, like the forcing scheme will be discussed.

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