Photo of Saeed Salehi

Saeed Salehi

Associate Professor

Data-driven and AI methods for high-fidelity Computational Fluid Dynamics (CFD).

Background

I am an Associate Professor of Fluid Mechanics at Linköping University. I study complex fluid flows using high-fidelity Computational Fluid Dynamics (CFD). My research combines data-driven approaches and machine learning with CFD to develop efficient and reliable tools for simulation, model order reduction, control, and uncertainty quantification.

I am first and foremost a Computational Fluid Dynamics (CFD) specialist. To me, CFD extends beyond a black box, and I am particularly engaged in open-source development, especially with OpenFOAM. My doctoral research focused on uncertainty quantification of turbulent flows in turbomachinery, where I developed sparse and efficient methods to assess operational and geometrical uncertainties and applied robust optimization under uncertainty. During my postdoc at Chalmers, I developed numerical methods for transient simulations of hydraulic turbines and expanded into reduced-order modeling, studying approaches such as POD, SPOD, DMD, and sparsity-promoting DMD.

More recently, my research has moved toward integrating machine learning with CFD. I have explored flow control using Deep Reinforcement Learning (DRL) within OpenFOAM, and multi-fidelity physics-informed neural networks for solving PDEs. Altogether, my current line of research lies at the intersection of high-fidelity CFD and data-driven methods, aiming to develop efficient, robust, and trustworthy approaches for the simulation, understanding, and control of complex flows.

Picture below illustrates the scope of my research.

Illustration.

CV in brief

Education

  • 2018: PhD in Mechanical Engineering, University of Tehran
    I developed efficient uncertainty quantification methods for fluid flows using polynomial chaos expansion. I introduced compressed sensing and multifidelity l1 minimization to reduce computational costs, and demonstrated how operational and geometrical uncertainties impact flow behavior and performance of tubomachines.

Appointments

  • 2025 –Associate Professor of Fluid Mechanics at Linköping University.
  • 2023 – 2025Researcher, Chalmers University of Technology – Chalmers Industriteknik (CIT)
    Studied the application of artificial intelligence and machine learning for understating and controlling fluid flows.
  • 2019 – 2023Postdoctoral researcher, Chalmers University of Technology
    Developed numerical methods in OpenFOAM for transient hydraulic turbine simulations and advanced data-driven approaches, including reduced-order modeling with POD and DMD.

Publications:

For a complete list of publications, visit:

 

Full Academic CV

For a full academic CV, kindly check out the GitHub repo: github.com/salehisaeed/CV

 

 

Research

Overview

My research explores how Computational Fluid Dynamics (CFD) can be advanced through data science and machine learning to better understand, predict, and control complex flow systems. The focus is on developing efficient, robust, and generalizable methods that address both fundamental and applied problems in turbulent flows and turbomachinery. The following picture provides an overview of my research interests.

Robust and efficient flow control

A major line of research focuses on developing Deep Reinforcement Learning (DRL) algorithms for active control of fluid flows. DRL offers a promising approach for discovering sophisticated strategies that go beyond classical methods, but current frameworks often face challenges of efficiency, robustness, and generalization.

  • Goal: push DRL toward realistic high-Reynolds-number flows.
  • Approach: multifidelity learning, transfer learning, robust learning under uncertainties.
  • Impact: new possibilities for turbulence control and a deeper understanding of flow physics.

Illustration.

Robust and efficient control of fluid flows

High-fidelity simulation of turbomachinery flows

A central part of my research is the use and development of high-fidelity CFD methods for complex flow fields in turbomachinery. These flows are inherently challenging due to their strong unsteadiness, turbulence, and sensitivity to transient operating conditions. During my postdoctoral work at Chalmers, I developed advanced numerical methods in OpenFOAM for simulating the transient operation of hydraulic turbines, including novel semi-implicit mesh-deformation techniques to capture rapid changes in operating points. Such simulations provide the detailed flow data required for analysis, validation, and the development of reduced-order and data-driven models.

Illustration.

Highly resolved DES simulation of the Timişoara swirl generator, illustrating complex flow filed, including a strong rotating vortex rope. For more information, read the open-access article: Modal analysis of vortex rope using dynamic mode decomposition.

Illustration.

Vortical structures (red) and stagnant regions (blue) of the Francis-99 turbine during the shutdown operation. For more information, read the open-access article: An in-depth numerical analysis of transient flow field in a Francis turbine during shutdown.

Full startup operation of the Francis-99 turbine. Click on the box to see the video. For more information, read the open-access article: Flow-induced pulsations in Francis turbines during startup - A consequence of an intermittent energy system.

Reduced-order modeling and data-driven analysis

I am much interested in exploring physics through Reduced-order modeling (ROM) and data-driven decomposition methods, including POD, SPOD, DMD, sparsity-promoting DMD, and non-linear autoencoders. These methods make it possible to extract coherent structures from large datasets and construct low-dimensional models for prediction and control.

Temporal dynamics of the dominant DMD mode of the Timişoara swirl generator. Click on the box to see the video. For more information, read the open-access article: Modal analysis of vortex rope using dynamic mode decomposition.

Uncertainty quantification and robust optimization

I have studied Uncertainty Quantification (UQ) algorithms for complex turbulent flows. I developed sparse polynomial chaos expansion, compressed sensing, and multifidelity 1 -minimization methods to make UQ more efficient and applicable to industrial problems.

  • Explored both operational and geometrical uncertainties in engineering applications.

  • Demonstrated robust optimization under uncertainty in practical flows.

Illustration.

Robust design of gas turbine blade. For more information, read the article: Robust optimization of the NASA C3X gas turbine vane under uncertain operational conditions.

Publications

Selected publications

Cover of publication ''
Saeed Salehi, Mehrdad Raisee, Michel J. Cervantes, Ahmad Nourbakhsh (2017)

Computers & Fluids , Vol.154 , s.296-321 Continue to DOI

Cover of publication ''
Saeed Salehi, Håkan Nilsson (2024)

Physics of fluids , Vol.36 Continue to DOI

Cover of publication ''
Saeed Salehi (2024)

Meccanica (Milano. Print) , Vol.60 , s.1673-1693 Continue to DOI

Article in journal

Mohammad Sheikholeslami, Saeed Salehi, Wengang Mao, Arash Eslamdoost, Håkan Nilsson (2025) Physics-informed neural networks with hard and soft boundary conditions for linear free surface waves Physics of fluids, Vol. 37, Article 087158 Continue to DOI
Faiz Azhar Masoodi, Saeed Salehi, Rahul Goyal (2024) Reorganization of flow field due to load rejection driven self-mitigation of high load vortex breakdown in a Francis turbine Physics of fluids, Vol. 36, Article 094110 Continue to DOI
Jonathan Fahlbeck, Håkan Nilsson, Mohammad Hossein Arabnejad, Saeed Salehi (2024) Performance characteristics of a contra-rotating pump-turbine in turbine and pump modes under cavitating flow conditions Renewable energy, Vol. 237, p. 121605-121605, Article 121605 Continue to DOI
Saeed Salehi, Håkan Nilsson (2024) Modal analysis of vortex rope using dynamic mode decomposition Physics of fluids, Vol. 36, Article 024122 Continue to DOI
Faiz Azhar Masoodi, Saeed Salehi, Rahul Goyal (2024) Formation and evolution of vortex breakdown consequent to post design flow increase in a Francis turbine Physics of fluids, Vol. 36, Article 025116 Continue to DOI
Saeed Salehi (2024) An efficient intrusive deep reinforcement learning framework for OpenFOAM Meccanica (Milano. Print), Vol. 60, p. 1673-1693 Continue to DOI
Jonathan Fahlbeck, Håkan Nilsson, Saeed Salehi (2023) Surrogate based optimisation of a pump mode startup sequence for a contra-rotating pump-turbine using a genetic algorithm and computational fluid dynamics Journal of Energy Storage, Vol. 62, p. 106902-106902, Article 106902 Continue to DOI
Saeed Salehi, Håkan Nilsson (2023) A semi-implicit slip algorithm for mesh deformation in complex geometries, implemented in OpenFOAM Computer Physics Communications, Vol. 287, p. 108703-108703, Article 108703 Continue to DOI

Organisation