A dynamic spectrally-enriched subgrid-scale model for preferential concentration of inertial particles in turbulence

In this study, a new subgrid-scale (SGS) model for turbulent velocity fluctuations is proposed for large-eddy simulations (LES) of multiphase flows. The modeled velocity contains scales smaller than the LES grid resolution thereby enabling, in principle, the calculation of small-scale phenomena such as particle preferential concentration and interfacial corrugation dynamics. The deterministic construction of the spectrally-enriched velocity in physical space is based on 1) the modeling of the smallest-resolved eddies of sizes comparable to the LES grid size via approximate deconvolution and 2) the reconstruction of SGS fluctuations via non-linear synthesis of small-scale turbulence. The new model does not contain tunable parameters, can be deployed in non-uniform grids, and is applicable to inhomogeneous flows subject to arbitrary boundary conditions. The performance of the model is assessed in LES of isotropic turbulence laden with inertial particles, where improved agreement with direct numerical simulation results is obtained in the dispersed-phase statistics. Application to wall-modeled LES of particle-laden channel flow will be presented.