Stefanie Günther


Computational Mathematics Group
Department of Mathematics and
Center for Computational Engineering Science (CCES)
RWTH Aachen University
Schinkelstr. 2
D-52062 Aachen
Germany

Room: 216a (Rogowski building, 2nd floor)
Phone: +49 (0)241 80 98 675
Email: Stefanie Günther

Office Hours

by appointment, please send me an Email.


About Me

After my studies of mathematics with minor subject computer science at University of Trier I am now a PhD student at RWTH Aachen University and a research assistant in the Scientific Computing group of Prof. Gauger at TU Kaiserslautern. I am an associated fellow at the Aachen Institute of Advanced Study in Computational Engineering Science (AICES) and an active member of the SIAM Student Chapter Aachen.


Research Interests

I am focusing on the simultaneous One-shot method for solving PDE-constrained optimization problems. The method has proven to be very efficient for optimization with steady-state PDEs. However, it's application to unsteady PDEs in aerodynamic context is challenging and is the topic of my PhD thesis. A special focus is on optimization with turbulent, i.e. chaotic dynamics. Here, a regularization is needed for computing meaningful sensitivities of the output quantities. This leads to the so-called Least Squares Shadowing problem - a minimization problem that has to be solved in the space-time domain. Most recently, I also got interested in parallel-in-time One-shot optimization. I am currently developing an adjoint solver for the multigrid in time integration library XBraid that enables efficient sensitivity computation for unsteady PDEs on multiple processors. It's usage in a One-shot optimization framework has great potential for speeding up the optimization process with unsteady dynamics.

In short:

  • Simultaneous One-Shot Optimization with unsteady PDEs
  • Optimal control of unsteady flows
  • Discrete and continuous adjoint method for sensitivity computation of steady and unsteady PDEs
  • One-shot optimization with chaotic dynamics
  • Parallel-in-Time optimization with unsteady PDEs


Teaching

Teaching assistant for


Resume

  • 2012 - present: Doctoral candidate at RWTH Aachen University, Germany
  • 2014 - present: Research assistant at Chair of Scientific Computing, SciComp, TU Kaiserslautern, Germany
  • 2012 - 2014: Research assistant at Dept. of Mathematics, MATHCCES, RWTH Aachen University, Germany
  • 2012: Diploma (equivalent to M. Sc.) in Mathematics with V. Schulz and N. Gauger
  • 2008 - 2012: Student assistant at Research Group on PDE-Constrained Optimization, University of Trier, Germany
  • 2006 - 2012: Studies in Applied Mathematics with minor in Computer Science, University of Trier, Germany
  • 1992 - 2005: School Education
  • 1985: Born in Neuwied, Germany


Publications

  • S. Günther, N.R. Gauger, J.B. Schroder: A Non-Intrusive Parallel-in-Time Adjoint Solver with the XBraid Library, submitted to Computing and Visualization in Science (2017), arXiv preprint: https://arxiv.org/pdf/1705.00663.pdf
  • S. Günther, N.R. Gauger, Q. Wang: A framework for simultaneous aerodynamic design optimization in the presence of chaos, Journal of Computational Physics (2017), pp. 387-398, DOI 10.1016/j.jcp.2016.10.043, http://www.sciencedirect.com/science/article/pii/S0021999116305411
  • S. Günther, N.R. Gauger, Q. Wang: Simultaneous single-step one-shot optimization with unsteady PDEs, Journal of Computational and Applied Mathematics, Vol. 294, pp. 12-22, 2016, http://dx.doi.org/10.1016/j.cam.2015.07.033, arXiv preprint
  • S. Günther, N.R. Gauger, Q. Wang: Extension of the One-Shot Method for Optimal Control with Unsteady PDEs, Computational Methods in Applied Sciences, Vol. 36, pp. 127-142, 2015
  • T. Bosse, N.R. Gauger, S. Günther, L.Kaland et al.: Optimal design with bounded retardation for problems with non-separable adjoints, International Series of Numerical Mathematics, Vol. 165, pp. 67-84, 2014
  • T. Bosse, N.R. Gauger, A.Griewank, S. Günther, V.Schulz: One-shot approaches to design optimization, International Series of Numerical Mathematics, Vol. 165, pp. 43-66, 2014
  • S. Günther: Simultane Optimierung unter PDE-Nebenbedingungen - Ein Vergleich zweier One-Shot-Methoden, Diploma Thesis, University of Trier, 2012. thesis


Talks

  • S. Günther, N.R. Gauger, J.B. Schroder: Adjoint Sensitivity Computation for the Parallel Multigrid Reduction in Time Software Library XBraid, 5th Workshop on Parallel-in-Time Integration, Nov 2017, Banff, Canada
  • S. Günther, N.R. Gauger, Q. Wang: Simultaneous PDE-constrained Optimization in Chaotic Dynamics - A framework for optimal control of highly separated flows, GAMM Annual Meeting, March 2016, Braunschweig, Germany
  • S. Günther, N.R. Gauger, Q. Wang: Fixed-Point Iterations for Simultaneous One-Shot Optimization of Unsteady Flows, SIAM CSE 2015, March 14-18, Salt Lake City, USA
  • S. Günther, N.R. Gauger, Q. Wang: Towards Efficient One-Shot Optimization with Unsteady Navier-Stokes Equations, GAMM 2014, March 10-14 2014, Erlangen, Germany
  • S. Günther, N.R. Gauger, Q. Wang: Extension of the One-Shot Method for Optimal Control with Unsteady PDEs, EUROGEN 2013, October 7-10 2013, Las Palmas de Gran Canaria, Spain
  • S.Günther, N.R. Gauger: One-Shot Optimization with unsteady PDE constraints, Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, March 04 2014, Cambridge, USA
  • S. Günther, E. Özkaya, A. Nemili, N.R. Gauger: Optimal Active Separation Control on Airfoils using Discrete Adjoint Approach, SIAM CSE 2013, February 25 - March 1 2013, Boston, USA
Last modified: 2017/05/05 15:09