A note on the consistency of Hybrid Eulerian/Lagrangian approach to multiphase flows

TL;DR

This paper discusses potential inconsistencies in hybrid Eulerian/Lagrangian models for turbulent multiphase flows, emphasizing the importance of model compatibility to avoid non-physical results, especially with tracer particles.

Contribution

It highlights the need for consistent turbulence modeling in hybrid approaches and demonstrates the impact of inconsistencies through computational examples.

Findings

Inconsistent turbulence coupling can lead to non-physical results.

Coupling strategies significantly affect simulation accuracy.

Inconsistencies are critical for tracer-limit particles.

Abstract

The aim of the present paper is to introduce and to discuss inconsistencies errors that may arise when Eulerian and Lagrangian models are coupled for the simulations of turbulent poly-dispersed two-phase flows. In these hydrid models, two turbulence models are in fact implicitely used at the same time and it is essential to check that they are consistent, in spite of their apparent different formulations. This issue appears in particular in the case of very-small particles, or tracer-limit particles, and it is shown that coupling inconsistent turbulence models (Eulerian and Lagrangian) can result in non-physical results, notably for second-order fluid velocity moments. This problem is illustrated by some computations for fluid particles in a turbulent channel flow using several coupling strategies.