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Gregor Gassner's main research interest are the reliable and efficient simulation of non-linear multi-scale problems governed by conservation laws. Examples include the compressible Euler and Navier-Stokes equations (aerodynamics, aeroacoustics, turbulence and shocks), the ideal and resistive magnetohydrodynamic equations (plasma physics, astrophysics, space physics), and the shallow water equations (oceanography). Due to the non-linear multi-scale character of such problems, millions and even billions of degrees of freedom are necessary to simulate real life behavior, which is only feasible when unleashing the power of todays largest super computers with hundred thousand compute cores and more: high performance computing is thus a major focus in all aspects of the design, analysis, and construction of new numerical methods and algorithms. In particular, the design of space and time adaptive algorithms offers great potential in providing realiability, high fidelity, and the desired efficacy. The final, still open aspect and the ultimate research goal in Gassner's ERC Starting Grant is robustness in addition to efficacy, i.e., the creation of an "un-crashable" solver. For more reseach details, see Research.

Strong scaling results on Blue Gene architecture of DG method with only one element (polynomial degree 7) on a processor for the final scaling test.

Selected Publications

  1. David Flad, Gregor J. Gassner. " On the use of kinetic energy preserving DG-schemes for large eddy simulation ", Journal of Computational Physics 350 (2017): 782-795. https://doi.org/10.1016/j.jcp.2017.09.004
  2. L. Friedrichs, D. C. D. R. Fernández, A. R. Winters, G. J. Gassner, D. W. Zingg, and J. Hicken. " Conservative and Stable Degree Preserving SBP Operators for Non-Conforming Meshes ", Journal of Scientific Computing (2017). https://doi.org/10.1007/s10915-017-0563-z
  3. G.J. Gassner, A.R. Winters and David A. Kopriva. " Split Form Nodal Discontinuous Galerkin Schemes with Summation-By-Parts Property for the Compressible Euler Equations ", Journal of Computational Physics 327 (2016): 39-66. https://doi.org/10.1016/j.jcp.2016.09.013
  4. D. Derigs, A.R. Winters, G.J. Gassner and S. Walch. " A Novel High-Order, Entropy Stable, 3D AMR MHD Solver with Guaranteed Positive Pressure ", Journal of Computational Physics 317 (2016): 223-256. https://doi.org/10.1016/j.jcp.2016.04.048
  5. G.J. Gassner, M. Staudenmaier, F. Hindenlang, M. Atak, C.-D. Munz. " A Space-Time Adaptive Discontinuous Galerkin Scheme ", Computers & Fluids, 117: 247-261, 2015. https://doi.org/10.1016/j.compfluid.2015.05.002
  6. Th. von Larcher, A. Beck, R. Klein, I. Horenko, P. Metzner, M. Waidmann, D. Igdalov, G. Gassner and C.-D. Munz. " Towards a Framework for the Stochastic Modelling of Subgrid Scale Fluxes for Large Eddy Simulation ", Meteorologische Zeitschrift, 24: 313-342, 2015.
  7. G. Gassner. " A skew-symmetric discontinuous Galerkin spectral element discretization and its relation to SBP-SAT finite difference methods ", SIAM Journal on Scientific Computing, 35: A1233-A1253, 2013. https://doi.org/10.1137/120890144
  8. G. Gassner, F. Lörcher, C.-D. Munz, J. S. Hesthaven. " Polymorphic nodal elements and their application in discontinuous Galerkin methods ", J. Comput. Phys., (228): 1573-1590, 2009. https://doi.org/10.1016/j.jcp.2008.11.012
  9. G. Gassner, F. Lörcher, C.-D. Munz. " A discontinuous Galerkin scheme based on a space-time expansion. II. Viscous flow equations in multi dimensions ", J. Sci. Comp., 34(3): 260-286, 2008. https://doi.org/10.1007/s10915-007-9169-1
  10. G. Gassner, F. Lörcher, C.-D. Munz. " A contribution to the construction of diffusion fluxes for finite volume and discontinuous Galerkin schemes ", J. Comput. Phys., 224(2): 1049-1063, 2007. https://doi.org/10.1016/j.jcp.2006.11.004