ILASS Americas 20th Annual Conference on Liquid Atomization and Spray Systems
May 2007, Chicago, Illinois
Multiphase LES-style spatial filtering provides a rigorous means of modeling flow over computationally-unresolved particles and droplets, without recourse to the point-particle limit. As such, it can be used to investigate the validity of point-particle models for particles of finite sizes, and to provide refinements that extend the range of validity of the models. We present results for the specific case of solid spherical particles, illustrating that a single-point-force model derived from the point-particle assumption produces reasonably accurate results at a particle Reynolds number of 1.0 for particles with diameters as large as 1/2 of the filter radius, but causes significant errors in the filtered centerline velocity and resolved-scale viscous dissipation at Reynolds numbers of 10 and 100 for particles with diameters as small as 1/16th of the filter radius. Further, we show that the addition of an axial dipole component to the standard single-point force provides a substantially improved model.