Abstract: Turbulent particle-laden flows give rise to spatial heterogeneity (e.g. clustering) characterized by two-point statistics. Most coarse-grained (i.e. two fluid) models only solve for one-point moments, limiting reproduction of important two-phase flow statistics. In this talk, we present set of equations describing the evolution of these flows that include fluctuating components of filtered fields --- a description of the level of clustering present in these flows. For dilute heavy particles settling in homogeneous isotropic turbulence, the averaged filtered drag and filtered Reynolds-stress like term that dictates enhanced settling is correlated to this description of volume fraction fluctuation. A data-driven approach that efficiently traverses parameter space in direct numerical simulations to inform closures is proposed, providing both descriptive insights and directions for future modeling. Further, a numerical crossflow experiment is proposed, yielding several advantages over traditional forced homogeneous isotropic turbulence for the study of turbulent particle-laden flows. The filtered volume fraction is shown to be valuable in that it may enable better fits for unclosed quantities related to particle drag and particle-phase momentum flux in coarse-grained simulations.


Contact: Silas Alben