This image shows Iryna Rybak

Iryna Rybak

Priv.-Doz. Dr.

Research assistant

Contact

+49 711 685 67647

Pfaffenwaldring 57
70569 Stuttgart
Deutschland
Room: 7.127

Office Hours

Wednesday, 11:30 - 12:30

Subject

Averaging theories and multiscale methods (homogenization, volume averaging, termodynamically constrained averaging theory, numerical upscaling, computation of effective properties)

Mathematical modelling (coupling free-flow and porous-medium systems, modelling flow and transport processes in porous media, porous-medium models with fluid-fluid interfacial area, sediment transport, mixed-dimensional models for fractured porous media)

Efficient numerical algorithms for multiphysics problems (domain decomposition, time splitting, multigrid, preconditioners, Newton-Krylov-methods, stability analysis, a priori error estimates)

Model validation and calibration (data-driven homogenisation based on neural networks, sensitivity analysis, model reduction, pore-scale modelling)

  1. 2024

    1. Strohbeck, P., Discacciati, M., Rybak, I.: Optimized Schwarz method for the Stokes-Darcy problem with generalized interface conditions. J. Comput. Phys. (submitted). (2024).
    2. Strohbeck, P., Rybak, I.: Efficient preconditioners for coupled Stokes-Darcy problems with MAC scheme: Spectral analysis and numerical study. J. Sci. Comput. (submitted). (2024).
    3. Ruan, L., Rybak, I.: Stokes-Brinkman-Darcy models for coupled fluid-porous systems: derivation, analysis and validation. Appl. Math. Comp.  (submitted). (2024).

  2. 2023

    1. Kröker, I., Oladyshkin, S., Rybak, I.: Global sensitivity analysis using multi-resolution polynomial chaos expansion for coupled Stokes-Darcy flow problems. Comput. Geosci. (2023). https://doi.org/10.1007/s10596-023-10236-z.
    2. Miller, C.T., Gray, W.G., Kees, C.E., Rybak, I., Shepherd, B.J.: Correction to: Modelling Sediment Transport in Three-Phase Surface Water Systems. J. Hydraul. Res. 61, 168–171 (2023). https://doi.org/10.1080/00221686.2022.2107580.
    3. Eggenweiler, E., Nickl, J., Rybak, I.: Justification of generalized interface conditions for Stokes-Darcy problems. In: Franck, E., Fuhrmann, J., Michel-Dansac, V., and Navoret, L. (eds.) Finite Volumes for Complex Applications X - Volume 1, Elliptic and Parabolic Problems. pp. 275–283. Springer Nature Switzerland (2023). https://doi.org/10.1007/978-3-031-40864-9_22.
    4. Strohbeck, P., Riethmüller, C., Göddeke, D., Rybak, I.: Robust and Efficient Preconditioners for Stokes--Darcy Problems. In: Franck, E., Fuhrmann, J., Michel-Dansac, V., and Navoret, L. (eds.) Finite Volumes for Complex Applications X---Volume 1, Elliptic and Parabolic Problems. pp. 375--383. Springer Nature Switzerland, Cham (2023).
    5. Eggenweiler, E., Rybak, I.: Higher-order coupling conditions for arbitrary flows in Stokes-Darcy systems. J. Fluid Mech. (submitted). (2023).
    6. Mohammadi, F., Eggenweiler, E., Flemisch, B., Oladyshkin, S., Rybak, I., Schneider, M., Weishaupt, K.: A Surrogate-Assisted Uncertainty-Aware Bayesian Validation Framework and its Application to Coupling Free Flow and Porous-Medium Flow. Comput. Geosci. (2023). https://doi.org/10.1007/s10596-023-10228-z.
    7. Strohbeck, P., Eggenweiler, E., Rybak, I.: A modification of the Beavers-Joseph condition for arbitrary flows to the fluid-porous interface. Transp. Porous Med. 147, 605–628 (2023). https://doi.org/10.1007/s11242-023-01919-3.
    8. Ruan, L., Rybak, I.: Stokes-Brinkman-Darcy models for coupled free-flow and porous-medium systems. In: Franck, E., Fuhrmann, J., Michel-Dansac, V., and Navoret, L. (eds.) Finite Volumes for Complex Applications X - Volume 1, Elliptic and Parabolic Problems. pp. 365–373. Springer Nature Switzerland (2023). https://doi.org/10.1007/978-3-031-40864-9_31.
    9. Strohbeck, P., Riethmüller, C., Göddeke, D., Rybak, I.: Robust and efficient preconditioners for Stokes-Darcy problems. In: Franck, E., Fuhrmann, J., Michel-Dansac, V., and Navoret, L. (eds.) Finite Volumes for Complex Applications X - Volume 1, Elliptic and Parabolic Problems. pp. 375–383. Springer Nature Switzerland (2023). https://doi.org/10.1007/978-3-031-40864-9_32.

  3. 2022

    1. Eggenweiler, E., Discacciati, M., Rybak, I.: Analysis of the Stokes-Darcy problem with generalised interface conditions. ESAIM Math. Model. Numer. Anal. 56, 727–742 (2022). https://doi.org/10.1051/m2an/2022025.

  4. 2021

    1. Rybak, I., Schwarzmeier, C., Eggenweiler, E., Rüde, U.: Validation and calibration of coupled porous-medium and free-flow problems using pore-scale resolved models. Comput. Geosci. 25, 621–635 (2021). https://doi.org/10.1007/s10596-020-09994-x.
    2. Wagner, A., Eggenweiler, E., Weinhardt, F., Trivedi, Z., Krach, D., Lohrmann, C., Jain, K., Karadimitriou, N., Bringedal, C., Voland, P., Holm, C., Class, H., Steeb, H., Rybak, I.: Permeability estimation of regular porous structures: a benchmark for comparison of methods. Transp. Porous Med. 138, 1–23 (2021). https://doi.org/10.1007/s11242-021-01586-2.
    3. Eggenweiler, E., Rybak, I.: Effective coupling conditions for arbitrary flows in Stokes-Darcy systems. Multiscale Model. Simul. 19, 731–757 (2021). https://doi.org/10.1137/20M1346638.

  5. 2020

    1. Rybak, I., Metzger, S.: A dimensionally reduced Stokes-Darcy model for fluid flow in fractured porous media. Appl. Math. Comp. 384, (2020). https://doi.org/10.1016/j.amc.2020.125260.
    2. Eggenweiler, E., Rybak, I.: Unsuitability of the Beavers-Joseph interface condition for filtration problems. J. Fluid Mech. 892, A10 (2020). http://dx.doi.org/10.1017/jfm.2020.194.
    3. Eggenweiler, E., Rybak, I.: Interface conditions for arbitrary flows in coupled porous-medium and free-flow systems. In: Klöfkorn, R., Keilegavlen, E., Radu, F., and Fuhrmann, J. (eds.) Finite Volumes for Complex Applications IX - Methods, Theoretical Aspects, Examples. pp. 345--353. Springer International Publishing (2020). https://doi.org/10.1007/978-3-030-43651-3_31.

  6. 2019

    1. Miller, C.T., Gray, W.G., Kees, C.E., Rybak, I.V., Shepherd, B.J.: Modeling sediment transport in three-phase surface water systems. J. Hydraul. Res. 57, (2019). https://doi.org/10.1080/00221686.2019.1581673.

  7. 2016

    1. Magiera, J., Rohde, C., Rybak, I.: A hyperbolic-elliptic model problem for coupled surface-subsurface  flow. Transp. Porous Media. 114, 425–455 (2016). https://doi.org/10.1007/S11242-015-0548-Z.
    2. Rybak, I., Magiera, J.: Decoupled schemes for free flow and porous medium systems. In: et al., T.D. (ed.) Domain Decomposition Methods in Science and Engineering XXII. pp. 613--621. Springer (2016). https://doi.org/10.1007/978-3-319-18827-0\_54.

  8. 2015

    1. Rybak, I.V., Gray, W.G., Miller, C.T.: Modeling two-fluid-phase flow and species transport in porous media. J. Hydrology. 521, 565--581 (2015). https://doi.org/10.1016/j.jhydrol.2014.11.051.
    2. Rybak, I., Magiera, J., Helmig, R., Rohde, C.: Multirate time integration for coupled saturated/unsaturated porous medium and free flow systems. Comput. Geosci. 19, 299–309 (2015). https://doi.org/10.1007/s10596-015-9469-8.

  9. 2014

    1. Rybak, I., Magiera, J.: A multiple-time-step technique for coupled free flow and porous medium  systems. J. Comput. Phys. 272, 327--342 (2014). https://doi.org/10.1016/j.jcp.2014.04.036.
    2. Rybak, I.: Coupling free flow and porous medium flow systems using sharp interface  and transition region concepts. In: Fuhrmann, J., Ohlberger, M., and Rohde, C. (eds.) Finite Volumes for Complex Applications VII - Elliptic, Parabolic and Hyperbolic Problems, FVCA 7. pp. 703--711. Springer (2014). https://doi.org/10.1007/978-3-319-05591-6_70.

  10. 2012

    1. Jackson, A.S., Rybak, I., Helmig, R., Gray, W.G., Miller, C.T.: Thermodynamically constrained averaging theory approach for modeling  flow and transport phenomena in porous medium systems: 9. Transition  region models. Adv. Water Res. 42, 71--90 (2012). https://doi.org/10.1016/j.advwatres.2012.01.006.

  11. 2011

    1. Mosthaf, K., Baber, K., Flemisch, B., Helmig, R., Leijnse, A., Rybak, I., Wohlmuth, B.: A coupling concept for two-phase compositional porous-medium and  single-phase compositional free flow. Water Resour. Res. 47, W10522 (2011). https://doi.org/10.1029/2011WR010685.

  12. 2009

    1. Ewing, R., Iliev, O., Lazarov, R., Rybak, I., Willems, J.: A simplified method for upscaling composite materials with high contrast  of the conductivity. SIAM J. Sci. Comp. 31, 2568--2586 (2009). https://doi.org/10.1137/080731906.

  13. 2008

    1. Iliev, O., Rybak, I.: On numerical upscaling for flows in heterogeneous porous media. Comput. Methods Appl. Math. 8, 60--76 (2008).

  14. 2007

    1. Ewing, R., Iliev, O., Lazarov, R., Rybak, I.: On two-level preconditioners for flow in porous media. Fraunhofer ITWM (2007).
    2. Iliev, O., Rybak, I., Willems., J.: On upscaling heat conductivity for a class of industrial problems. Fraunhofer ITWM (2007).
    3. Iliev, O., Rybak, I.: On approximation property of multipoint flux approximation method. Fraunhofer ITWM (2007).

  15. 2005

    1. Iliev, O., Rybak, I.: On numerical upscaling of flow in anisotropic porous media. In: Mathematisches Forschungsinstitut Oberwolfach Report No. 20. pp. 1162–1165 (2005).

  16. 2004

    1. Rybak, I.: Monotone and conservative difference schemes for elliptic equations  with mixed derivatives. Math. Model. Anal. 9, 169--178 (2004).
    2. Rybak, I.: Monotone and conservative difference schemes for equations with mixed  derivatives. Dokl. Akad. Navuk Belarusi. 48, 45--48 (2004).
    3. Rybak, I.: Monotone and conservative difference schemes for nonlinear nonstationary  equations and equations with mixed derivatives, (2004).
    4. Matus, P., Melnik, R., Wang, L., Rybak, I.: Applications of fully conservative schemes in nonlinear thermoelasticity:  modelling shape memory materials. Math. Comp. Simulation. 65, 489--509 (2004).
    5. Rybak, I.: Computational dynamics of shape memory alloys. In: Proc. of Lobachevski Mathematical Center. pp. 209--218. Kazan (2004).
    6. Matus, P., Rybak, I.: Difference schemes for elliptic equations with mixed derivatives. Comput. Methods Appl. Math. 4, 494--505 (2004).
    7. Rybak, I.: Monotone difference schemes for equations with mixed derivatives  in the case of boundary conditions of the third type. Proceedings of the National Academy of Sciences of Belarus, Series  of Physical-Mathematical Sciences. 40, 37--42 (2004).

  17. 2003

    1. Melnik, R., Wang, L., Matus, P., Rybak, I.: Computational aspects of conservative difference schemes for shape  memory alloys applications. Lecture Notes in Comput. Sci. 2668, 791--800 (2003).
    2. Matus, P., Melnik, R., Rybak, I.: Fully conservative difference schemes for nonlinear models describing  dynamics of materials with shape memory. Dokl. Akad. Navuk Belarusi, 47(1):15–17, 2003. 47, 15--17 (2003).
    3. Matus, P., Rybak, I.: Monotone difference schemes for nonlinear parabolic equations. Differential Equations. 39, 1013--1022 (2003).
    4. Rybak, I.: Difference schemes for nonlinear models describing dynamic behaviour  of shape memory alloys. In: Condensed State Physics: XI Republican Scientific Conference, Grodno,  Belarus, April 23�25, 2003. pp. 200–203 (2003).
Winter Term 2024/25

Mathematische Programmierung 1 BSc

Mathematische Modellierung
Summer Term 2024

Mathematische Programmierung 2 BSc
Winter Term 2023/24

Mathematische Programmierung 1 BSc

Hauptseminar: Matrix Computations
Summer Term 2023

Advanced Numerics of Partial Differential Equations
Winter Term 2022/23

Höhere Mathematik I für Ingenieurstudiengänge (Lineare Algebra und Geometrie)

Masterseminar: Multiscale modelling and numerics: how to bridge scales
Winter Term 2021/22

Mathematische Programmierung 1 BSc

Homogenization theory and computations

Numerische Mathematik 1
Summer Term 2021

Numerical methods for differential equations

Seminar: Saddle-Point Problems
Winter Term 2020/21

Mathematik 1 für Wirtschaftswissenschaftler (WebEx)
Summer Term 2020

Advanced Numerics of Partial Differential Equations (WebEx)

Masterseminar: Multiskalenmodellierung in der numerischen Mathematik (WebEx)
Winter Term 2019/20

Mathematik 1 für Wirtschaftswissenschaftler

Seminar: Efficient numerical methods for large linear systems
Summer Term 2019

Numerische Lineare Algebra
Mathematische Programmierung für Lehramt
Winter Term 2018/19 Masterseminar Simulation Technology
Summer Term 2017 Numerische Lineare Algebra
Winter Term 2016/17 Numerische Fluiddynamik
Summer Term 2016 Mathematische Modellierung
Winter Term 2015/16 Numerische Verfahren für Mehrskalenprobleme
Winter Term 2014/15 Höhere Mathematik I für Ingenieurstudiengänge (Lineare Algebra und Geometrie)
Winter Term 2012/13 Poröse Medien: Modellierung, Analysis und Numerik
Summer Term 2012 Höhere Mathematik I für Ingenieurstudiengänge (Lineare Algebra und Geometrie)
Jan. 2016

Habilitation in Mathematics (University of Stuttgart, Germany)
Nov. 2001 -- Nov. 2004

PhD in Physics and Mathematics (Institute of Mathematics, National Academy of Sciences of Belarus)
Sep. 1996 -- Jun. 2001 MSc in Applied Mathematics (Belarusian State University)
Apr. 2000 -- Jun. 2001 MSc in Economical Cybernetics (Belarusian State University)
2022-2025 Principal investigator in ANR-DFG Project FLUPOR: "Generalised Interface Conditions for Multi-Dimensional Inertial Flows in Fluid-Porous Systems" with Philippe Angot, Aix-Marseille Université (1 postdoc position for 24 months, 2 PhD positions for 36 months)
2022-2025 Principal investigator in Collaborative Research Centre (SFB) 1313 "Interface-Driven Multi-Field Processes in Porous Media – Flow, Transport and Deformation'' (Phase 2), German Research Foundation (DFG), Project A03 "Development of interface concepts using averaging techniques" (1 PhD position for 48 months)
2018-2021 Principal investigator in Collaborative Research Centre (SFB) 1313 "Interface-Driven Multi-Field Processes in Porous Media – Flow, Transport and Deformation'', German Research Foundation (DFG), Project A03 "Development of interface concepts using averaging techniques"
2016-2017 Eigene Stelle, ``Mathematische Modellierung und Numerik von Übergangsbereichen zwischen porösen Medien und freien Strömungen'',  DFG Projekt, RY 126/2-2
2012-2015 Eigene Stelle, ``Mathematische Modellierung und Numerik von Übergangsbereichen zwischen porösen Medien und freien Strömungen'',  DFG Projekt, RY 126/2-1
2007-2009 Project participant, ``Development of multilevel algorithms for simulation of fluid flows in porous media'', Belarusian Republican Foundation for Fundamental Research, F07MS-054
2004-2007 Project participant, ``Hydrogeological and geo-environmental simulations: a contribution to the algorithms and advanced applications'', INTAS-03-50-4395
2004-2006 Principal investigator, ``Development of monotone and conservative difference schemes for problems of mathematical physics with mixed derivatives'', Belarusian Republican Foundation for Fundamental Research, F04M-136
  • Advances in Computational Mathematics
  • Advances in Water Resources (Certificate of Excellence in Reviewing, 2013)
  • Applied Mathematics and Computation
  • Applied Mathematical Modelling
  • Applied Numerical Mathematics
  • Computational and Applied Mathematics
  • Computational Geosciences
  • Computers and Mathematics with Applications
  • Computer Methods in Applied Mechanics and Engineering
  • Geofluids
  • IMA Journal of Numerical Analysis
  • International Journal of Heat and Mass Transfer
  • Journal of Computational and Applied Mathematics
  • Journal of Computational Physics
  • Journal of Hydraulic Research
  • Journal of Hydrology
  • Journal of Porous Media
  • Journal of Scientific Computing
  • Mathematics of Computation
  • Mathematical Reviews
  • Nonlinearity
  • Numerical Methods for Partial Differential Equations
  • SIAM Journal on Numerical Analysis
  • Transport in Porous Media
  • Water Resources Research

Postdoctoral Researchers:
    Elissa Eggenweiler

Ph.D. Students:
    Linheng Ruan
    Paula Strohbeck
   Joscha Nickl (Aix-Marseille-Université, France)

Master Students:
    Sven Kahle
    Maurice Wolf

PhD theses:

  • P. Strohbeck: Development of interface concepts using averaging techniques
    since November 2022
  • J. Nickl: Generalised interface conditions for multi-dimensional inertial flows in fluid-porous systems: mathematical analysis and model validation (Aix-Marseille Universite, France), since October 2022
  • L. Ruan: Generalised interface conditions for multi-dimensional inertial
    flows in fluid-porous systems: mathematical modelling and numerical analysis, since May 2022
  • E. Eggenweiler: Interface conditions for arbitrary flows in Stokes-Darcy systems: derivation, analysis and validation (defended 2022)

Master theses:

  • S. Kahle: Data-driven homogenization and boundary layer theory based on neural networks, 2023
  • M. Wolf: Data-driven homogenization for two-phase flows in porous media, 2023
  • P. Strohbeck: Efficient preconditioners for Stokes-Darcy problems, 2022
  • N. Nutsch: Optical flow methods for PIV analysis in
    fractured porous media, 2022
  • J. Nickl: Generalised interface conditions for Stokes–Darcy problems
    with symmetric stress tensor, 2022
  • A. Baric: Boundary layers for coupled problems in porous media, 2019
  • Y. Öztürk: Upscaling of capillary network structures, 2018

Bachelor theses:

  • F. Castor: Preconditioners for saddle point problems in fluid dynamics, 2021
  • S. Kahle: Stochastic gradient descent for image registration, 2021
  • M. Wolf: Data-driven homogenization based on neural networks for permeability estimation, 2020
  • P. Strohbeck: Optimization of sharp interface location for coupled porous-medium and free-flow systems, 2020
  • N. Nutsch: Numerical optimization methods for image registration with mutual information, 2020
  • A.-K. Kapfenstein: Numerical optimization algorithms for image registration, 2020
  • J. Flad: Image Registration using Mutual Information, 2019
  • T. Schwaderer: Krylov subspace methods for diffusion equations with
    discontinuous coefficients, 2019
  • L. Ruan: Newton-Krylov Methods for Porous Media Flows, 2019
  • A. Savanovic: Efficient numerical methods for ill-conditioned linear
    systems, 2019
  • L. Igel: Numerical methods for equilibrium and kinetic models, 2018
  • D. Beyer: Newton-Krylov methods for unsaturated flows in porous media, 2018
  • S. Özkan: Homogenisation of flow and transport in porous media, 2018
  • S. Matskevich: Mathematical modelling of filtration processes, 2018
  • E. Eggenweiler: Mathematical modelling of flows in fractured porous media,
    2017
  • A. Baric: Mathematical modelling of coupled free and subsurface water
    flow, 2017
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