@misc{HarlanderBorciaKrebs, author = {Harlander, Uwe and Borcia, Ion-Dan and Krebs, Andreas}, title = {Nonnormality increases variance of gravity waves trapped in a tilted box}, series = {Geophysical \& Astrophysical Fluid Dynamics}, volume = {113}, journal = {Geophysical \& Astrophysical Fluid Dynamics}, number = {5/6}, issn = {1029-041}, doi = {10.1080/03091929.2018.1549660}, pages = {602 -- 622}, language = {en} } @misc{MalteseMelettideOliveiraAbideViazzoetal., author = {Maltese Meletti de Oliveira, Gabriel and Abide, St{\´e}phane and Viazzo, Stephane and Krebs, Andreas and Harlander, Uwe}, title = {Experiments and long-term high-performance computations on amplitude modulations of strato-rotational flows}, series = {Geophysical \& Astrophysical Fluid Dynamics}, volume = {115}, journal = {Geophysical \& Astrophysical Fluid Dynamics}, number = {3}, issn = {1029-0419}, doi = {10.1080/03091929.2020.1795647}, pages = {297 -- 321}, language = {en} } @inproceedings{MalteseMelettideOliveiraRaspoSeeligetal., author = {Maltese Meletti de Oliveira, Gabriel and Raspo, Isabelle and Seelig, Torsten and Viazzo, Stephane and Randriamampianina, Anthony and Abide, St{\´e}phane and Krebs, Andreas and Harlander, Uwe}, title = {On the instability of radially sheared and axially stratified vortex flow}, series = {European Geosciences Union, General Assembly 2018, Vienna, Austria}, booktitle = {European Geosciences Union, General Assembly 2018, Vienna, Austria}, publisher = {European Geophysical Society}, address = {Katlenburg-Lindau}, language = {en} } @phdthesis{Krebs, author = {Krebs, Andreas}, title = {On solving nonlinear variational inequalities by p-version finiteelements}, abstract = {This thesis introduces and analyzes a p-version FEM for variationalinequalities resulting from obstacle problems for some nonlinearelliptic partial differential operators. We approximate the solutionby controlling the obstacle condition in images of the Gauss-Lobattopoints. We show existence and uniqueness for thediscrete solution u_p from the p-version for the obstacle problem. Weprove the convergence of u_p towards the solution with respectto the energy norm, and assuming some additional regularity for thesolution we derive an a priori error estimate. In numericalexperiments the p-version turns out to be superior to the h-versionconcerning the convergence rate and the number of unknowns needed toachieve a certain exactness of the approximation.}, language = {de} } @inproceedings{FuttererZaussingerKochetal., author = {Futterer, Birgit and Zaussinger, Florian and Koch, Sandy and Krebs, Andreas and Egbers, Christoph}, title = {Nonlinear effects and associated instabilities in iso-viscous and temperature-dependent viscous thermal convection in spherical shells, the geophysical flow simulation experiment integrated in Fluid Science Laboratory}, language = {en} } @inproceedings{FuttererZaussingerKrebsetal., author = {Futterer, Birgit and Zaussinger, Florian and Krebs, Andreas and Egbers, Christoph}, title = {Non-linear effects and associated instabilities in spherical Rayleigh-Benard experiments with variation of the viscosity contrast}, language = {en} } @misc{FuttererKrebsPlesaetal., author = {Futterer, Birgit and Krebs, Andreas and Plesa, Ana-Catalina and Zaussinger, Florian and Hollerbach, Rainer and Breuer, Doris and Egbers, Christoph}, title = {Sheet-like and plume-like thermal flow in a spherical convection experiment performed under microgravity}, series = {Journal of Fluid Mechanics}, volume = {vol. 735}, journal = {Journal of Fluid Mechanics}, issn = {1750-6859}, doi = {10.1017/jfm.2013.507}, pages = {647 -- 683}, language = {en} } @article{KrebsGraeffFrielingetal., author = {Krebs, Andreas and Graeff, Christian and Frieling, Isolde and Kurz, Bodo and Timm, Wolfram and Engelke, Klaus and Gl{\"u}er, Claus-C.}, title = {High resolution computed tomography of the vertebrae yields accurate information on trabecular distances if processed by 3d fuzzy segmentation approaches}, language = {en} } @article{KrebsStephan, author = {Krebs, Andreas and Stephan, Ernst P.}, title = {A p-version finite element method for nonlinear elliptic variational inequalities in 2D}, doi = {10.1007/s00211-006-0035-0}, abstract = {This article introduces and analyzes a p-version FEM for variational inequalities resulting from obstacle problems for some quasi-linear elliptic partial differential operators. We approximate the solution by controlling the obstacle condition in images of the Gauss-Lobatto points. We show existence and uniqueness for the discrete solution u p from the p-version for the obstacle problem. We prove the convergence of u p towards the solution with respect to the energy norm, and assuming some additional regularity for the solution we derive an a priori error estimate. In numerical experiments the p-version turns out to be superior to the h-version concerning the convergence rate and the number of unknowns needed to achieve a certain exactness of the approximation.}, language = {en} } @techreport{NoellSeiboldKrebs, author = {Noell, M. and Seibold, G{\"o}tz and Krebs, Andreas}, title = {Excitations in disordered superconductors: Inclusion of long-range Coulomb interactions}, publisher = {HLRN}, address = {Berlin}, isbn = {978-3-00-063360-7}, pages = {269}, language = {en} }