The pseudo-direct numerical simulation method for solving turbulent multiphase flows

GIMENEZ, JUAN M.; IDELSOHN, SERGIO; OÑATE, EUGENIO

Hamburgo

Conferencia; VII International Conference on Particle-Based Methods (PARTICLES 2021); 2021

CIMNE Congress Boreau

The Pseudo-Direct Numerical Simulation (P-DNS) method is a general approach to solve multiscale fluid dynamics phenomena overcoming the computational burden associated with the direct numerical resolution of the governing equations. In P-DNS, both the coarse scale and the fine scale are solved numerically. The most expensive part of the computations, the solution of the fine scale, is parametrized to be performed offline and store the results in dimensionless databases. This latter allows us to construct synthetic models to emulate the fine scale behavior when coarse scale solutions are computed. In this work, a multiphase representative volume element (RVE) is designed for the case of a dispersed flow of heavy particles in air. A set of numerical experiments for a range of volume fractions, particle distribution sizes, and inertial forces introduced as shear loads are solved using an Eulerian-Lagrangian approach. Quantitative results of the statistically stationary turbulent state are obtained, along with the description of the interaction forces between the phases, and the velocity and the dispersion of the particulate phase. The database of RVE results is stored in an artificial neural network to facilitate its use in the coarse scale solver via a fast interpolation technique. Global case studies are analyzed employing a continuum approach for the particulate phase, highlighting the differences and similarities found using the fine-scale model developed vis-a-vis the standard empirical approaches used by two-phase-like methods.