Modeling of inhomogeneous particle-laden turbulence

Substantial past effort has focused on developing accurate models of particle-fluid force coupling and subgrid Reynolds stress closures that can be used in Euler-Lagrange and Euler-Euler simulations, but mostly in the homogeneous limit when particles are uniformly distributed and subjected to a uniform form. The focus of this talk will be to account for the effect of inhomogeneity that arises both from the non-uniform distribution of particles as well as spatial variations in the mesoscale flow. Characterization of such inhomogeneity must involve parameters such as volume fraction gradient and velocity gradient tensor, in addition to mean particle Reynolds number and volume fraction. A summary of current understanding and most promising future directions will be discussed.