Computation of strongly coupled multifield interaction in particle–fluid systems

The present work develops a flexible and robust solution strategy to resolve coupled systems comprised of large numbers of flowing particles embedded within a fluid. A model problem, consisting of particles which may undergo inelastic collisions in the presence of near-field forces, is considered. The particles are surrounded by a continuous interstitial fluid which is assumed to obey the compressible Navier–Stokes equations. Thermal effects are also considered. Such particle/fluid systems are strongly coupled, due to the mechanical forces and heat transfer induced by the fluid onto the particles and vice-versa. Because the coupling of the various particle and fluid fields can dramatically change over the course of a flow process, a primary focus of this work is the development of a recursive “staggering” solution scheme, whereby the time-steps are adaptively adjusted to control the error associated with the incomplete resolution of the coupled interaction between the various solid particulate and continuum fluid fields. A central feature of the approach is the ability to account for the presence of particles within the fluid in a straightforward manner that can be easily incorporated within any standard computational fluid mechanics code based on finite difference, finite element or finite volume type discretization. A three dimensional example is provided to illustrate the overall approach.