Hybrid particle-grid methods for the study of differential diffusion in turbulent flows

This paper is devoted to the development and application of hybrid methods combining, on the one hand, semi-lagrangian methods for the advection-diffusion of scalars, and, on the other hand, either finite volume or spectral methods, depending on the flow geometry, for the Navier-Stokes equations. A particular focus is made on the accuracy and scalability of the methods. These methods are then used to study differential diffusion of scalars on two canonical cases: Homogeneous Isotropic Turbulence and a jet flow. We first characterize differential diffusion in terms of spectral distribution. We then use the Reynolds decomposition to bring out the different mechanisms involved in the energy budget of the scalar and we analyze their spatial distribution. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This paper focuses on the development and application of hybrid methods for advection-diffusion of scalars, combining semi-Lagrangian methods with either finite volume or spectral methods for Navier-Stokes equations based on flow geometry. The methods are applied to study differential diffusion in Homogeneous Isotropic Turbulence and a jet flow, analyzing mechanisms through spectral distribution and Reynolds decomposition.