Dr Lionel Agostini | CNRS Researcher

Diving into Multi-Scale Wall-Bounded Turbulence

Dynamics, Theory, and Control Mechanisms

Advancing wall-bounded turbulence research through innovative data-driven methodologies for energy-efficient applications

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Research Motivation

My research is driven by the critical need to enhance energy efficiency and reduce environmental impact across various engineering and natural systems. Wall-bounded turbulent flows, prevalent in applications from transportation to energy generation, are characterized by high friction drag and complex heat transfer mechanisms. Understanding and controlling these multi-scale phenomena is paramount for developing innovative solutions. Specifically, my work aims to unravel the intricate dynamics of turbulence to devise strategies for significant drag reduction, thereby lowering fuel consumption and emissions, and to optimize heat transfer processes, crucial for improving the performance of systems like heat exchangers in solar energy applications and advanced engine designs. By integrating high-fidelity simulations, experimental insights, and data-driven approaches, the ultimate goal is to translate fundamental discoveries into tangible benefits for a more sustainable future.

Illustration of drag reduction concepts in turbulent flow
Conceptual illustration of drag reduction mechanisms.
Illustration of heat transfer enhancement in fluid dynamics
Conceptual illustration of heat transfer enhancement.

About Me

I am a Chargé de Recherche (Tenured Researcher) at the French National Centre for Scientific Research (CNRS), based at the Pprime Institute in Poitiers, France. With over 15 years of experience in fluid mechanics research, my work focuses on understanding and controlling wall-bounded turbulent flows to improve energy efficiency and thermal management in various engineering applications.

Dr Lionel Agostini

Current Position & Responsibilities

  • Tenured Researcher (CNRS) - Pprime Institute, Fluid Dynamics Department, CURIOSITY Team
  • Member of the Scientific Evaluation Committee (CES 60) - University of Poitiers
  • Member of the Pprime Communication Committee
  • Principal Investigator - ANR JCJC INFERENCE Project (2024-2028)
  • PhD Supervision - Currently supervising research in turbulence modelling and heat transfer

Areas of Expertise

Fluid Mechanics Wall-bounded Turbulence Computational Fluid Dynamics (CFD) Machine Learning & AI Flow Control & Optimisation Heat Transfer Enhancement Reduced-Order Modelling (ROM) High-Fidelity Simulations (DNS/LES)
20+ Journal Articles
30+ Conference Papers
1250+ Citations
18 H-index

Research Leadership & Vision (HDR)

My Habilitation à Diriger des Recherches (HDR) encapsulates a significant body of work, reflecting a mature research program and a forward-looking vision for fluid mechanics. It underscores my contributions to understanding multi-scale turbulence, developing innovative control strategies, and integrating machine learning for deeper physical insights and practical applications.

Key themes from my HDR include the nuanced interplay of large- and small-scale structures in wall-bounded flows, the strategic manipulation of these dynamics for enhanced thermal-fluid performance, and the development of data-driven frameworks that bridge fundamental research with engineering solutions.

Key Contributions & Insights from HDR

  • Advanced understanding of scale interactions in turbulent flows.
  • Novel methodologies for flow control and drag reduction.
  • Pioneering use of Machine Learning for turbulence modelling and analysis.
  • Development of predictive models for complex fluid systems.
  • Mentorship and supervision leading to impactful research outcomes.

Future Research Directions

Building on this foundation, my future research will focus on:

  • Developing next-generation, AI-augmented turbulence models for high-Reynolds number industrial applications.
  • Exploring adaptive and real-time flow control systems leveraging reinforcement learning for optimal energy efficiency.
  • Investigating multi-physics phenomena where turbulence interacts with other physical processes (e.g., combustion, phase change).
  • Championing open science practices and collaborative research to tackle grand challenges in fluid mechanics.

The goal is to translate fundamental discoveries into tangible benefits for society, particularly in sustainable energy and advanced manufacturing.

Explore Full HDR Manuscript

Academic & Professional Journey

2020 – Present

Chargé de Recherche (Tenured Researcher)

CNRS - Institut Pprime, Université de Poitiers, France

  • Leading research on multi-scale interactions in wall-bounded turbulence.
  • Developing novel flow control strategies for drag reduction and heat transfer enhancement.
  • Applying data-driven methods (Machine Learning, AI) to fluid dynamics modelling.
  • Securing and managing competitive research grants (e.g., ANR JCJC INFERENCE PI).
  • Supervising PhD students and mentoring junior researchers.
  • Contributing to institutional committees (Scientific Evaluation, Communication).
Research Leadership ANR Projects PhD Supervision Machine Learning Flow Control Heat Transfer
2019 – 2020

Research Associate

Imperial College London, Department of Aeronautics, UK

  • Contributed to the EU H2020 HIFI-TURB project (Supervisor: Prof. Peter Vincent).
  • Analysed high-fidelity LES/DNS data for innovative turbulence model development.
EU Project Turbulence Modelling High-Fidelity Simulations
2016 – 2019

Research Associate

Imperial College London, Department of Aeronautics, UK

  • Investigated near-wall turbulence and drag reduction at high Reynolds numbers.
  • Worked within the EU-China project DRAGY (Supervisor: Prof. Michael Leschziner).
EU-China Project Drag Reduction High Reynolds Number
2014 – 2017

Research Associate

Ohio State University, Department of Mechanical & Aerospace Engineering, USA

  • Conducted research on near-wall turbulence, shockwave/boundary layer interaction, and jet flows.
  • Funded by the US Air Force (Supervisor: Prof. Datta Gaitonde).
US Air Force Funding Shockwave Interaction Supersonic Jets
2013 – 2014

Research Associate

Imperial College London, Department of Aeronautics, UK

  • Focused on drag reduction in turbulent channel flow using spanwise wall oscillations.
  • EPSRC funded project (Supervisor: Prof. Michael Leschziner).
EPSRC Funding Drag Reduction Flow Control
2011 – 2013

Research Associate

IUSTI, Aix-Marseille University, France

  • Investigated control of Görtler vortices using plasma actuators.
  • ANR funded project (Supervisor: Prof. Patrick Bontoux).
ANR Project Flow Control Görtler Vortices
2008 – 2011

PhD in Fluid Mechanics

IUSTI, Aix-Marseille University, France

Thesis: "Unsteadiness in separated supersonic flow". Supervisors: Prof. Jean-Paul Dussauge & Dr Pierre Dupont. Awarded with highest honours (Très Honorable).

PhD Supersonic Flow Flow Instability
2007 – 2008

Master's Degree in Fluid Dynamics and Aeroacoustics

Paris Sud University (Paris XI), France

Graduated with high distinction (Mention Bien). Ranked 1st in class (30 students).

MSc Fluid Dynamics Aeroacoustics
2005 – 2006

Bachelor's Degree in Physics

Aix-Marseille University, France

Graduated with high distinction (Mention Bien).

BSc Physics
View Complete Academic Résumé

Core Research Themes

My research delves into the fundamental physics of turbulent flows, particularly wall-bounded turbulence, ubiquitous in engineering and nature. I develop innovative methodologies combining high-fidelity simulations with data-driven approaches to analyse, model, and control these complex systems, aiming to enhance energy efficiency and thermal management.

Wall-bounded turbulence structure visualization 1
Wall-bounded turbulence structure visualization 2
Wall-bounded turbulence structure visualization 3
Wall-bounded turbulence structure visualization 4

Wall-bounded Turbulence

Investigating the multi-scale dynamics, focusing on how large outer structures interact with and modulate near-wall turbulence. Pioneering new techniques for scale separation and statistical analysis to quantify interactions, challenging traditional paradigms and improving understanding of friction and heat transfer at high Reynolds numbers.

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Drag Reduction & Heat Transfer

Exploring innovative flow control techniques, like spanwise wall oscillations, to manipulate near-wall turbulence. Achieved preferential enhancement of heat transfer over drag (breaking the Reynolds analogy), with significant implications for thermal management efficiency in engineering systems.

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Machine Learning in Fluid Dynamics

Developing and applying advanced machine learning (e.g., auto-encoders, symbolic regression) to extract physical insights from complex flow data. Creating reduced-order models and coupling data-driven modelling with control optimisation for a powerful framework to understand and manipulate complex flows.

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Concept of secondary flow control

Secondary Flow Instabilities

Exploiting natural flow instabilities (e.g., Görtler vortices on concave surfaces) to enhance heat transfer efficiently. Research focuses on controlling these instabilities using minimal energy input (e.g., plasma actuators) for applications like aerospace heat exchanger design.

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Explore My Research in Detail

Current Research Projects

I currently lead and participate in several research projects focused on advancing our understanding of turbulent flows and developing innovative control strategies:

2024 – 2028

ANR JCJC INFERENCE

Modelling near-wall turbulence at high Reynolds numbers and developing predictive models for wall flux fluctuations.

Project Lead (PI) 330k€
2022 – 2026

ANR SOLAIRE

Improving heat transfer in solar receivers through active control methods and machine learning optimisation.

Co-Investigator 179k€ (Pprime share)
2023 – 2027

ANR MUFDD

Data-driven modelling of urban canopy flows using advanced machine learning techniques.

Team Member 182k€ (Pprime share)
2025 – 2029

SAFRAN Aircraft Engines Collaboration

Enhancing heat transfer in aircraft engines through active control of secondary flow instabilities.

Project Lead (Pprime) 4 years
View All Projects

Advanced Methodologies

My research leverages a synergistic combination of cutting-edge computational techniques, sophisticated data analysis, and innovative machine learning approaches to unravel the complexities of turbulent flows and devise effective control strategies.

High-Fidelity DNS/LES

Utilising direct numerical simulations (DNS) and large-eddy simulations (LES) to obtain detailed data for in-depth analysis of turbulent structures and interactions.

Advanced Statistical Analysis

Employing sophisticated statistical methods (joint/conditional PDFs, spectral analysis) to quantify relationships between scales and flow properties.

Scale Separation Techniques

Applying innovative methods like auto-encoders and empirical mode decomposition to isolate large and small-scale fluctuations and study their interactions.

Machine Learning Applications

Developing and applying ML algorithms (auto-encoders, symbolic regression, reinforcement learning) to extract insights, create interpretable models, and optimise control.

Selected Publications

Preferential Enhancement of Convective Heat Transfer Over Drag Via Near-Wall Turbulence Manipulation Using Spanwise Wall Oscillations

L. Guérin, C. Flageul, L. Cordier, S. Grieu, & L. Agostini

International Journal of Heat and Fluid Flow, Vol. 1010:109564 (2024)

PDF DOI

Auto-encoder-assisted analysis of amplitude and wavelength modulation of near-wall turbulence by outer large-scale structures in channel flow at Reτ=5200

L. Agostini & M. A. Leschziner

Physics of Fluids, Vol. 34 (2022)

PDF DOI

Statistical analysis of outer large-scale/inner-layer interactions in channel flow subjected to oscillatory drag-reducing wall motion using a multiple-variable joint PDF methodology

L. Agostini & M. A. Leschziner

Journal of Fluid Mechanics, Vol. 923 (2021)

PDF DOI

Exploration and prediction of fluid dynamical systems using Auto-Encoder technology

L. Agostini

Physics of Fluids, Vol. 32(6):067103 (2020)

PDF DOI
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Get In Touch

Contact Information

Location

Institut Pprime, CNRS UPR 3346
Dept. Fluides, Thermique, Combustion
Bâtiment H2 - SP2MI, TSA 41123
11 Boulevard Marie et Pierre Curie
86073 POITIERS CEDEX 9, France

Phone

+33 (0)5 49 49 69 45

Academic & Professional Profiles

Affiliations

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