A Multiscale Approach for the Numerical Simulation of Turbulent Flows with Droplets

• Published in: Archives of computational methods in engineering Vol. 28; no. 6; pp. 4185 - 4204
• Main Authors: Gimenez, Juan M., Idelsohn, Sergio R., Oñate, Eugenio, Löhner, Rainald
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2021; Springer Nature B.V
• Subjects: Air flow; Direct numerical simulation; Droplets; Dynamic response; Engineering; Mathematical and Computational Engineering; Mathematical models; Modulation; Multiscale analysis; Nonlinear response; S.I. : Modeling and Simulation of Infectious Diseases; Shear forces; Simulation; Turbulence; Turbulent flow; Water drops
• ISSN: 1134-3060; 1886-1784
• DOI: 10.1007/s11831-021-09614-6

A multiscale approach for the detailed simulation of water droplets dispersed in a turbulent airflow is presented. The multiscale procedure combines a novel representative volume element (RVE) with the Pseudo Direct Numerical Simulation (P-DNS) method. The solution at the coarse-scale relies on a synthetic model, constructed using precomputed offline RVE simulations and an alternating digital tree, to characterize the non-linear dynamic response at the fine-scale. A set of numerical experiments for a wide range of volume fractions, particle distribution sizes, and external shear forces in the RVE are carried out. Quantitative results of the statistically stationary turbulent state are obtained, and the turbulence modulation phenomenon due to the presence of droplets is discussed. The developed synthetic model is then employed to solve global scale simulations of flows with airborne droplets via the P-DNS method. Improved predictions are obtained for flow conditions where turbulence modulation is noticeable.