Homogeneous Shear Cluster-induced Turbulence

Previous work has introduced homogeneous cluster-induced turbulence (CIT) as a canonical flow that may be studied for particle-laden flow model development. Homogeneous CIT is a two-way coupled flow in which a periodic domain of fluid is seeded with heavy, inertial particles. The momentum coupling between the phases results in turbulent-like fluctuations in the fluid phase and clustering in the particle phase that is characteristic of many particle-laden flows. As a step towards understanding particle-laden flow in boundary layers, in this work we examine the effect of homogeneous shear on CIT. We study the effects of varying the shear rate and shear direction on clustering and the dimensionality of the turbulent fluctuations. We find that at high shear rates, regardless of the shear direction, the turbulent fluctuations approach a one-component state and the clusters disappear. Horizontally oriented shear tends to impede the trajectory towards the one-component state. At low shear rates, the dynamics remain close to CIT regardless of the shear direction. Finally, we evaluate a Reynolds Stress Model by comparing its predictions with the simulation results in this study.