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Accueil du site > Évènements > Séminaires > Séminaires IRPHE > Archives IRPHE > 2017

Jeudi 1 juin 2017/ IRPHE

publié le

Séminaire exceptionnel IRPHE - I2M

Subgrid-scale modeling and wavelet analysis of particle-laden turbulent flows

Orateur : Maxime Bassenne
Center for Turbulence Research, Stanford University, CA, USA

Abstract : The preferential concentration of inertial particles is an important effect in multi-phase turbulent flows of practical relevance. The wide range of scales and flow structures present in high-Reynolds number flows cause accumulation of particles in clouds. The spatial heterogeneities arising in the spatial distribution of particles have important consequences on the relative dispersion and inter-phase coupling with the turbulent environment.

This work is divided in two parts. First, a new model is proposed for large-eddy simulations of small inertial particles in turbulent flows. The model is based on the use of elliptic differential filters. It does not require any tunable parameters, involves no significant computational overhead, and is flexible enough to be deployed in any type of flow solvers and grids. The model is shown to improve the prediction of the disperse-phase statistics. Second, wavelet-based tools that provide simultaneous information in physical and spectral spaces are described to analyze the phenomenon of preferential-concentration : (1) wavelet multi-resolution analyses are used to investigate the spatially localized spectral characteristics of turbulence sampled by particles accumulated in clusters and (2) a method referred to as Coherent Cluster Extraction is described that decomposes a Eulerian particle number-density field into the sum of a coherent (organized) and an incoherent (disorganized) components. The coherent component structurally bears the clusters of particles at a strikingly low compression rate. A direct application of the CCE method to radiative heat transfer simulations is described in the form of a grid-adaptation.

Date et lieu : jeudi 1 juin à 11h en salle de séminaires IRPHE