# Laboratoire de Mécanique des Fluides et d’Acoustique - UMR 5509

LMFA - UMR 5509
Laboratoire de Mécanique des Fluides et d’Acoustique
Lyon
France

## Modélisation de la turbulence

Outre nos travaux classiques de turbulence homogène et isotrope, les modèles spectraux en deux points de type EDQNM (Eddy Damped Quasi-Normal Markovian) ont été étendus pour la turbulence homogène stratifiée instablement et pour la turbulence en rotation confinée verticalement.
En simulation des grandes échelles, un modèle de sous-maille de type REDLES bâti sur les fluctuations a été développé afin d’améliorer la prédiction de la turbulence dans les décollements de coin des compresseurs, avec la perspective d’en améliorer le contrôle.
Par ailleurs, des techniques récentes d’assimilation de données ont permis —outre l’amélioration de la technique de flot optique— le développement de modèles de sous-maille pour la simulation des grandes échelles du mélange turbulent, en faisant appel à la théorie de l’estimateur optimal et à des outils d’apprentissage supervisé.

Personnels principalement impliqués : F. Godeferd, C. Cambon, W Bos, J. Scott, L. Shao, E. Lévêque, C. Corre, J.-P. Bertoglio ;
Doctorants et Post-Doctorants : Y. Zhu, V. Mons, A. Vollant, A. Vadrot ;

Collaborations : CEA/DAM, M2P2, LEGI, NASA, équipe Turbomachines.

Publications associées :

Article dans J. Fluid Mech. (2021)

### Three-dimensional turbulence without vortex stretching

Wouter Bos

We consider three-dimensional turbulence from which vortex stretching is removed. The resulting system conserves enstrophy, but does not conserve kinetic energy. Using spectral closure, it is (...)

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Article dans Computers & Fluids (2020)

### Turbulence modelling analysis in a corner separation flow

Jean-François Monier, Feng Gao, Jérôme Boudet & Liang Shao

This paper studies RANS turbulence modelling for a linear compressor cascade corner separation flow, using large-eddy simulation results as reference. The Boussinesq and the quadratic (...)

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Article dans Phys. Rev. Fluids (2020)

### Production and dissipation of kinetic energy in grid turbulence

Wouter Bos

In grid turbulence, not so far behind the grid, an average flow can be observed with a close to sinusoidal velocity profile, corresponding to the wakes behind the grid bars. The kinetic energy of (...)

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Article dans Phys. Rev. Letters (2020)

### Generation of Atmospheric Turbulence with Unprecedentedly Large Reynolds Number in a Wind Tunnel

Lars Neuhaus, Michael Hölling, Wouter Bos & Joachim Peinke

Generating laboratory flows resembling atmospheric turbulence is of prime importance to study the effect of wind fluctuations on objects such as buildings, vehicles, or wind turbines. A novel (...)

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Article dans Phys. Rev. E (2020)

### Linearly forced isotropic turbulence at low Reynolds numbers

Wouter Bos, Faouzi Laadhari & Wesley Agoua

The forcing strength needed to sustain a flow using linear forcing is investigated. A critical Reynolds number $R_c$ is determined, based on the longest wavelength allowed by the system, the (...)

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Article dans Computers & Fluids (2020)

### Reducing the background anisotropy by using hexagonal Fourier transform in two-dimensional turbulent flows

J. Chai, Le Fang & Jean-Pierre Bertoglio

The two-dimensional hexagonal Fourier transform is introduced to reduce the background anisotropy in the numerical calculations with periodic conditions. Comparing to traditional Fourier (...)

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Article dans Journal of Turbulence (2020)

### Staircase scaling of short-time energy transfer in turbulence

Le Fang, T. Wu & Wouter Bos

It is illustrated that a sharply truncated initial kinetic energy spectrum evolves to a staircase-shaped spectrum at short times. This effect is directly associated with the triadic nature of the (...)

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Article dans J. Fluid Mech. (2019)

### Nonlinear spectral model for rotating sheared turbulence

Ying Zhu, Claude Cambon, Fabien. Godeferd & Aziz Salhi

We propose a statistical model for homogeneous turbulence undergoing distortions, which improves and extends the MCS model by Mons, Cambon & Sagaut (2016). The spectral tensor of two-point (...)

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Article dans Phys. Rev. letters (2019)

### Power fluctuations in turbulence

Wouter J. T. Bos & Rémi Zamansky

To generate or maintain a turbulent flow, one needs to introduce kinetic energy. This energy injection necessarily fluctuates and these power fluctuations act on all turbulent excited length (...)

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Article dans J. Turbul. (2018)

### Advanced spectral anisotropic modelling for shear flows

Antoine Briard, Benoît-Joseph Gréa, Vincent Mons, Claude Cambon, Thomas Gomez & Pierre Sagaut

In this work, the spectral modelling developed in MCS (Mons, Cambon, Sagaut. J Fluid Mech. 2016) for shear-driven turbulence is further analysed and then improved. First, using self-similarity (...)

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Article dans Comput. Fluids (2018)

### Improved Vortex Method for Large-eddy Simulation Inflow Generation

BaolinXie, Feng Gao, Jérôme Boudet, Liang Shao & Lipeng Lu

The generation of turbulent inflow conditions in large-eddy simulation (LES) is a key ingredient for general applications of LES in both academic turbulent flows and industrial designs with (...)

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Article dans Phys. Rev. Fluids (2017)

### Reynolds and Prandtl number scaling of viscous heating in isotropic turbulence

Andrey Pushkarev, Guillaume Balarac, and Wouter J. T. Bos

Viscous heating is investigated using high-resolution direct numerical simulations. Scaling relations are derived and verified for different values of the Reynolds and Prandtl numbers. The (...)

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Article dans C. R. Méc. (2017)

### Multipoint turbulence structure and modelling : The legacy of Antoine Craya

Claude Cambon

Some elements are given on the very multiform career of Antoine Craya. In addition to a strong involvement in applied hydraulics in Grenoble, he was very influential on the research of his (...)

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Article dans J. Turbul. (2017)

### Subgrid-scale scalar flux modelling based on optimal estimation theory and machine-learning procedures

A. Vollant, G. Balarac, C. Corre

New procedures are explored for the development of models in the context of large eddy simulation (LES) of a passive scalar. They rely on the combination of the optimal estimator theory with (...)

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Article dans Phys. Rev. Fluids (2017)

Wouter J.T. Bos, Robert Rubinstein

Recent experiments and simulations have shown that unsteady turbulent flows display a universal behavior at short and intermediate times, different from classical scaling relations. The origin of (...)

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Article dans Chin. J. Aeronauti. (2017)

### Parameter study on numerical simulation of corner separation in LMFA-NACA65 linear compressor cascade

Gao Feng, Ma Wei, Sun Jinjing, Jérôme Boudet, Xavier Ottavy, Liu Yangwei, Lu Lipeng, Shao Liang

Large-eddy simulation (LES) is compared with experiment and Reynolds-averaged Navier-Stokes (RANS), and LES is shown to be superior to RANS in reproducing corner separation in the LMFA-NACA65 (...)

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Article dans Comput. Fluids (2017)

### Anisotropic triadic closures for shear-driven and buoyancy-driven turbulent flows

Claude Cambon, Vincent Mons, Benoît-Joseph Gréa, Robert Rubinstein

We show how two-point turbulence models based on triadic closures, initially developed for homogeneous isotropic turbulence, can be applied to anisotropic turbulent flows. Efficient numerical (...)

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Article dans Phys. Rev. E (2016)

### Relation of the fourth-order statistical invariants of velocity gradient tensor in isotropic turbulence

Le Fang, Y.J. Zhang, J. Fang, Ying Zhu

We show by direct numerical simulations (DNSs) that in different types of isotropic turbulence, the fourth-order statistical invariants have approximately a linear relation, which can be (...)

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Article dans Chem. Eng. Res. Des. (2016)

### Shear improved Smagorinsky model for large eddy simulation of flow in a stirred tank with a Rushton disk turbine

Satish Malik, Emmanuel Lévêque, Mounir Bouaif, Lionel Gamet, Églantine Flottes, Serge Simoens & Mahmoud El Hajem

Large eddy simulation (LES) is a very attractive method for simulations of reactive flows for a wide range of Reynolds number. In this approach, the effects observed at the large scales (for (...)

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Article dans Phys. Fluids (2016)

### A dynamic regularized gradient model of the subgrid-scale stress tensor for large-eddy simulation

Antoine Vollant, Guillaume Balarac & Christophe Corre

Large-eddy simulation (LES) solves only the large scales part of turbulent flows by using a scales separation based on a filtering operation. The solution of the filtered Navier-Stokes equations (...)

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Article dans Renew. Energy (2016)

### Fast power output prediction for a single row of ducted cross-flow water turbines using a BEM-RANS approach

Favio Dominguez, Jean-Luc Achard, Jerônimo Zanette, Christophe Corre

A numerical model is proposed to efficiently compute the power produced by a row of Vertical Axis Water Turbines (VAWTs) deployed in parallel for various water flow conditions. As the (...)

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Article dans Comput. Fluids (2016)

### A Kalman filter adapted to the estimation of mean gradients in the large-eddy simulation of unsteady turbulent flows

Jérôme Boudet, Emmanuel Lévêque, Pierre Borgnat, Adrien Cahuzac, Marc C. Jacob

A computationally-efficient method based on Kalman filtering is introduced to capture “on the fly” the low-frequency (or very large-scale) patterns of a turbulent flow in a large-eddy simulation (...)

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Article dans Phys. Fluids (2015)

### Short-time evolution of Lagrangian velocity gradient correlations in isotropic turbulence

Le Fang, Wouter J. T. Bos & Guodong D. Jin

We show by direct numerical simulation (DNS) that the Lagrangian cross correlation of velocity gradients in homogeneous isotropic turbulence increases at short times, whereas its auto-correlation (...)

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Article dans Phys. Fluids (2015)

### Large-eddy simulation of 3-D corner separation in a linear compressor cascade

Feng Gao, Wei Ma, Gherardo Zambonini, Jérôme Boudet, Xavier Ottavy, Lipeng Lu & Liang Shao

The increase of the thrust/weight ratio of aircraft engines is extremely restricted by different 3-D flow loss mechanisms. One of them is the corner separation that can form at the junction (...)

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Article dans Proc. IMechE Part A, J. Power Energy (2015)

### Unsteady behavior of corner separation in a compressor cascade : Large eddy simulation and experimental study

Feng Gao, Gherardo Zambonini, Jérôme Boudet, Xavier Ottavy, Lipeng Lu, Liang Shao

The present study carried out a pure large eddy simulation (LES) on a NACA65 linear compressor cascade (chord-based Reynolds number : 382 000), at an incidence angle of 4°. In this configuration, (...)

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Article dans J. Turbul. (2015)

### Scalar and tensor spherical harmonics expansion of the velocity correlation in homogeneous anisotropic turbulence

Robert Rubinstein, Susan Kurien & Claude Cambon

The representation theory of the rotation group is applied to construct a series expansion of the correlation tensor in homogeneous anisotropic turbulence. The resolution of angular dependence is (...)

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Article dans Europhys. Lett. (2014)

### Introduction of longitudinal and transverse Lagrangian velocity increments in homogeneous and isotropic turbulence

Emmanuel Lévêque & Aurore Naso

Based on geometric considerations, longitudinal $(\delta u_\parallel^(L)(\tau))$ and transverse $(\delta u_\perp^(L)(\tau))$ Lagrangian velocity increments are introduced as components along, and (...)

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Article dans Phys. Fluids (2014)

### Depletion of nonlinearity in two-dimensional turbulence

Andrey V. Pushkarev & Wouter J. T. Bos

The strength of the nonlinearity is measured in decaying two-dimensional turbulence, by comparing its value to that found in a Gaussian field. It is shown how the nonlinearity drops following a (...)

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Article dans Sci. China, Phys. Mech. Astron. (2014)

### Recent understanding on the subgrid-scale modeling of large-eddy simulation in physical space

Le Fang, Liang Shao & Jean-Pierre Bertoglio

In the last 50 years, the methodology of large-eddy simulation (LES) has been greatly developed, while lots of different subgridscale (SGS) models have appeared. However, the understanding of the (...)

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