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I do research in Applied and Computational Mathematics, Scientific Computing, Computational Science, Machine Learning and Engineering Applications. I construct, analyze, implement and apply efficient numerical schemes for initial boundary value problems in multi-physics simulations. This includes lattice Boltzmann methods (LBMs) for coupled, stochastic and nonlinear partial differential equations that describe for example multi-component or turbulent fluid flow, blood flow and solid mechanics. Specifically, I focus on large-scale data generation, blending robust numerical schemes with uncertainty quantification and machine learning. I make extensive use of high-performance computers to explore previously unconsidered multi-dimensional parameter regimes for compute-heavy simulations in benchmarks and applications. Since 2018 I contribute to the open-source C++ library OpenLB.

Since 2023, I manage the LBRG Mathematical Modeling and Numerics Lab.
Since 2024, I am a member of the steering committee of the EU-funded project FALCON (doi: 10.3030/101138305).
Since 2024, I am an associate editor of the Elsevier journal Examples and Counterexamples.

About me: From 2011 to 2018, I studied Mathematics (BSc, MSc) at KIT, Germany, and KTH, Sweden. In 2023, I completed my doctorate in Mathematics (PhD) at KIT with funded research visits at UFRGS, Brazil and ETH Zürich, Switzerland. Since 2023, I am a postdoc at KIT. I received an ERASMUS+ EQF7 scholarship from 2016 to 2017, DAAD PPP mobility funding in 2019, the KIT Faculty Teaching Award in 2021, a KHYS Networking Grant in 2022 and a KHYS ConYS Grant in 2024. In 2024, I have been an Oberwolfach Leibniz Graduate Student and received an NHR Starter project. Since 2025, I hold a DAAD PRIME fellowship at KIT and ETH Zürich. My teaching activities and publications are listed below.

Link to Google Scholar

Theses (Open Topics)

Publications

1. S. Simonis, M.J. Krause. Limit consistency of lattice Boltzmann equations. ESAIM: M2AN 59(3):1271-1299 (2025)
2. E. Kummer, S. Simonis. Nonuniqueness of lattice Boltzmann schemes derived from finite difference methods. Examples and Counterexamples 7:100171 (2025)
3. F. Bukreev, A. Kummerländer, J. Jeßberger, D. Teutscher, S. Simonis, D. Bothe, M. J. Krause. Benchmark Simulation of Laminar Reactive Micromixing Using Lattice Boltzmann Methods. AIAA Journal 63(4):1295-1304 (2025)
4. S. Simonis, N. Hafen, J. Jeßberger, D. Dapelo, G. Thäter, M. J. Krause. Homogenized lattice Boltzmann methods for fluid flow through porous media – Part I: Kinetic model derivation. ESAIM: M2AN 59(2):789-813 (2025)
5. S. Simonis, J. Nguyen, S. J. Avis, W. Dörfler, M. J. Krause. Binary fluid flow simulations with free energy lattice Boltzmann methods. Discrete and Continuous Dynamical Systems - S 17(11):3278-3294 (2025)
6. M. Zhong, T. Xiao, M. J. Krause, M. Frank, S. Simonis. A stochastic Galerkin lattice Boltzmann method for incompressible fluid flows with uncertainties. Journal of Computational Physics 517:113344 (2024)
7. S. Ito, J. Jeßberger, S. Simonis, F. Bukreev, A. Kummerländer, A. Zimmermann, G. Thäter, G. R. Pesch, J. Thöming, M. J. Krause. Identification of reaction rate parameters from uncertain spatially distributed concentration data using gradient-based PDE constrained optimization. Computers & Mathematics with Applications 167:249-263 (2024)
8. S. Simonis, S. Mishra. Computing statistical Navier–Stokes solutions. In: R. Abgrall, M. Garavello, M. Lukácová-Medvidová, and K. Trivisa, Eds., Hyperbolic Balance Laws: Interplay between Scales and Randomness, Oberwolfach Rep. 21(1):634-637 (2024)
9. S. Simonis. Lattice Boltzmann Methods for Partial Differential Equations. PhD thesis (2023), Karlsruhe Institute of Technology (KIT).
10. F. Bukreev, S. Simonis, A. Kummerländer, J. Jeßberger, M. J. Krause. Consistent lattice Boltzmann methods for the volume averaged Navier–Stokes equations. Journal of Computational Physics 490:112301 (2023)
11. S. Simonis, M. Frank, M. J. Krause. Constructing relaxation systems for lattice Boltzmann methods. Applied Mathematics Letters 137:108484 (2023)
12. A. Mink, K. Schediwy, C. Posten, H. Nirschl, S. Simonis, M. J. Krause. Comprehensive Computational Model for Coupled Fluid Flow, Mass Transfer, and Light Supply in Tubular Photobioreactors Equipped with Glass Sponges. Energies 15(20):7671 (2022)
13. S. Simonis, M. J. Krause. Forschungsnahe Lehre unter Pandemiebedingungen. Mitteilungen der Deutschen Mathematiker-Vereinigung 30(1):43-45 (2022)
14. S. Simonis, D. Oberle, M. Gaedtke, P. Jenny, M. J. Krause. Temporal large eddy simulation with lattice Boltzmann methods. Journal of Computational Physics 454:110991 (2022)
15. S. Simonis, M. Haussmann, L. Kronberg, W. Dörfler, M. J. Krause. Linear and brute force stability of orthogonal moment multiple-relaxation-time lattice Boltzmann methods applied to homogeneous isotropic turbulence. Philosophical Transactions of the Royal Society A 379:20200405 (2021)
16. M. Haussmann, P. Reinshaus, S. Simonis, H. Nirschl, M. J. Krause. Fluid–Structure Interaction Simulation of a Coriolis Mass Flowmeter Using a Lattice Boltzmann Method. Fluids 6(4):167 (2021)
17. D. Dapelo, S. Simonis, M. J. Krause, J. Bridgeman. Lattice-Boltzmann coupled models for advection–diffusion flow on a wide range of Péclet numbers. Journal of Computational Science 51:101363 (2021)
18. M. Siodlaczek, M. Gaedtke, S. Simonis, M. Schweiker, N. Homma, M. J. Krause. Numerical evaluation of thermal comfort using a large eddy lattice Boltzmann method. Building and Environment 192:107618 (2021)
19. M. J. Krause, A. Kummerländer, S. J. Avis, H. Kusumaatmaja, D. Dapelo, F. Klemens, M. Gaedtke, N. Hafen, A. Mink, R. Trunk, J. E. Marquardt, M.-L. Maier, M. Haussmann, S. Simonis. OpenLB — Open source lattice Boltzmann code. Computers & Mathematics with Applications 81:258-288 (2021)
20. S. Simonis, M. Frank, M. J. Krause. On relaxation systems and their relation to discrete velocity Boltzmann models for scalar advection–diffusion equations. Philosophical Transactions of the Royal Society A 378:20190400 (2020)
21. M. Haussmann, S. Simonis, H. Nirschl, M. J. Krause. Direct numerical simulation of decaying homogeneous isotropic turbulence — numerical experiments on stability, consistency and accuracy of distinct lattice Boltzmann methods. International Journal of Modern Physics C 30(09):1950074 (2019)

A more complete list can be found here.

(Conference) Talks

1. S. Simonis, M. J. Krause. Exploratory Computation of Statistical Solutions to Incompressible Fluid Flows. SIAM Conference on Computational Science and Engineering (CSE25), March 3, 2025, Fort Worth Convention Center, Fort Worth, Texas, U.S.
2. S. Simonis, Computing Statistical Solutions of Fluid Flows with Lattice Boltzmann Methods. Séminaire de EDP - Physique Mathématique, November 5, 2024, University of Bordeaux, Bordeaux, France
3. S. Simonis, Computing Statistical Solutions of Fluid Flows. Séminaire Equations aux Dérivées Partielles, October 18, 2024, University of Strasbourg, Strasbourg, France
4. S. Simonis, B. Dorschner, I. V. Karlin, M. J. Krause. Spectral effects of entropic multi-relaxation for lattice Boltzmann methods. 33rd International Conference on Discrete Simulation of Fluid Dynamics (DSFD 2024), Juli 9-12, 2024, ETH Zürich, Zurich, Switzerland
5. S. Simonis. Turbulence models for lattice Boltzmann methods. March 5, 2024, Heidelberger Akademie für Wissenschaften, Heidelberg, Germany
6. S. Simonis, S. Mishra. Computing statistical Navier–Stokes solutions. Workshop 2409: Hyperbolic Balance Laws: Interplay between Scales and Randomness, February 25 - March 1, 2024, MFO, Oberwolfach, Germany
7. S. Simonis, M. J. Krause. Explorative computing for stable and consistent kinetic relaxation in lattice Boltzmann methods. 10th International Congress on Industrial and Applied Mathematics (ICIAM), August 20-25, 2023, Waseda University, Tokyo, Japan
8. S. Simonis. Turbulence models for lattice Boltzmann methods. June 5-9, 2023, University of Greenwich, London, UK
9. S. Simonis. Relaxation systems and lattice Boltzmann methods. October 21, 2022, Centre de Mathématiques Appliquées (CMAP), École Polytechnique, Palaiseau, France
10. S. Simonis, M. J. Krause. Brute force analysis of kinetic relaxation parameters for multiple-relaxation-time lattice Boltzmann methods. 31st International Conference on Discrete Simulation of Fluid Dynamics (DSFD 2022), August 22-26, 2022, Soochow University, Suzhou, China
11. S. Simonis, M. Frank, M. J. Krause. Constructive relaxation formalism for lattice Boltzmann methods. 92nd Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM 2022), August 15-19, 2022, RWTH Aachen University, Aachen, Germany
12. S. Simonis, M. J. Krause. Limit consistency of lattice Boltzmann equations. 18th International Conference for Mesoscopic Methods in Engineering and Science (ICMMES 2022), June 27 - July 1, 2022, La Rochelle University, La Rochelle, France
13. S. Simonis. Analysis of lattice Boltzmann methods. June 6, 2022, AGH University of Science and Technology, Krakow, Poland
14. S. Simonis. Turbulence models for lattice Boltzmann methods. June 7, 2022, AGH University of Science and Technology, Krakow, Poland
15. S. Simonis. Temporal large eddy simulation with lattice Boltzmann methods. November 24, 2021, Groupe de travail \"Schémas de Boltzmann sur réseau\", Institut Henri Poincaré, Online
16. S. Simonis, M. Frank, M. J. Krause. Discrete Velocity Boltzmann Models As Relaxation Systems for Scalar Advection–Diffusion Equations. 14th WCCM & ECCOMAS Congress 2020, Virtual Congress January 11-15, 2021
17. M. J. Krause, A. Kummerländer, S. Simonis. Fluid Flow Simulation with Lattice Boltzmann Methods on High Performance Computers. December 1, 2020, Advanced Modeling & Simulation (AMS) Seminar Series, NASA Advanced Supercomputing Division, Online
18. S. Simonis. Lattice Boltzmann methods for homogeneous isotropic turbulence. September 25, 2020, Institute of Fluid Dynamics, ETH Zürich, Switzerland
19. S. Simonis, M. Frank, M. J. Krause. Perturbation formalism of relaxation systems and the link to discrete velocity Boltzmann models. 29th International Conference on Discrete Simulation of Fluid Dynamics (DSFD 2020), July 13-18, 2020, Online
20. S. Simonis. Analysis of lattice Boltzmann methods. March 9, 2020, Technical University of Berlin (TU Berlin), Berlin, Germany
21. S. Simonis. Introduction to lattice Boltzmann methods. December 10, 2019, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
22. S. Simonis, M. Haussmann, H. Nirschl, M. J. Krause. Direct numerical simulation of decaying homogeneous isotropic turbulence with lattice Boltzmann methods. August 1, 2019, Indian Institute of Technology (IIT) Dharwad, Karnataka, India
23. M. Haussmann, S. Simonis, H. Nirschl, M. J. Krause. Direct numerical simulation of decaying homogeneous isotropic turbulence — numerical experiments on stability, consistency and accuracy of distinct lattice Boltzmann methods. 28th International Conference on Discrete Simulation of Fluid Dynamics (DSFD 2019), July 22-26, 2019, JNCASR Bangalore, India

Past and Upcoming Lectures and Courses