TY - GEN A1 - Harlander, Uwe A1 - Borcia, Ion-Dan A1 - Krebs, Andreas T1 - Nonnormality increases variance of gravity waves trapped in a tilted box T2 - Geophysical & Astrophysical Fluid Dynamics Y1 - 2019 U6 - https://doi.org/10.1080/03091929.2018.1549660 SN - 1029-041 VL - 113 IS - 5/6 SP - 602 EP - 622 ER - TY - GEN A1 - Maltese Meletti de Oliveira, Gabriel A1 - Abide, Stéphane A1 - Viazzo, Stephane A1 - Krebs, Andreas A1 - Harlander, Uwe T1 - Experiments and long-term high-performance computations on amplitude modulations of strato-rotational flows T2 - Geophysical & Astrophysical Fluid Dynamics Y1 - 2021 U6 - https://doi.org/10.1080/03091929.2020.1795647 SN - 1029-0419 SN - 0309-1929 VL - 115 IS - 3 SP - 297 EP - 321 ER - TY - CHAP A1 - Maltese Meletti de Oliveira, Gabriel A1 - Raspo, Isabelle A1 - Seelig, Torsten A1 - Viazzo, Stephane A1 - Randriamampianina, Anthony A1 - Abide, Stéphane A1 - Krebs, Andreas A1 - Harlander, Uwe T1 - On the instability of radially sheared and axially stratified vortex flow T2 - European Geosciences Union, General Assembly 2018, Vienna, Austria Y1 - 2018 UR - https://meetingorganizer.copernicus.org/EGU2018/EGU2018-8703.pdf N1 - EGU2018-8703 PB - European Geophysical Society CY - Katlenburg-Lindau ER - TY - THES A1 - Krebs, Andreas T1 - On solving nonlinear variational inequalities by p-version finiteelements N2 - 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. KW - Variationelle Ungleichungen KW - hp-Finite Elemente Methoden KW - a posteriori Fehlerschätzer KW - großskalierte Minimierung Y1 - 2004 UR - http://edok01.tib.uni-hannover.de/edoks/e01dh04/476288029.pdf ER - TY - CHAP A1 - Futterer, Birgit A1 - Zaussinger, Florian A1 - Koch, Sandy A1 - Krebs, Andreas A1 - Egbers, Christoph T1 - 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 Y1 - 2011 ER - TY - CHAP A1 - Futterer, Birgit A1 - Zaussinger, Florian A1 - Krebs, Andreas A1 - Egbers, Christoph T1 - Non-linear effects and associated instabilities in spherical Rayleigh-Benard experiments with variation of the viscosity contrast Y1 - 2011 ER - TY - GEN A1 - Futterer, Birgit A1 - Krebs, Andreas A1 - Plesa, Ana-Catalina A1 - Zaussinger, Florian A1 - Hollerbach, Rainer A1 - Breuer, Doris A1 - Egbers, Christoph T1 - Sheet-like and plume-like thermal flow in a spherical convection experiment performed under microgravity T2 - Journal of Fluid Mechanics Y1 - 2013 U6 - https://doi.org/10.1017/jfm.2013.507 SN - 1750-6859 VL - vol. 735 SP - 647 EP - 683 ER - TY - JOUR A1 - Krebs, Andreas A1 - Graeff, Christian A1 - Frieling, Isolde A1 - Kurz, Bodo A1 - Timm, Wolfram A1 - Engelke, Klaus A1 - Glüer, Claus-C. T1 - High resolution computed tomography of the vertebrae yields accurate information on trabecular distances if processed by 3d fuzzy segmentation approaches Y1 - 2008 ER - TY - JOUR A1 - Krebs, Andreas A1 - Stephan, Ernst P. T1 - A p-version finite element method for nonlinear elliptic variational inequalities in 2D N2 - 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. KW - FEM Y1 - 2007 UR - http://www.springerlink.com/content/p1126727200545k8/fulltext.pdf U6 - https://doi.org/10.1007/s00211-006-0035-0 ER - TY - RPRT A1 - Noell, M. A1 - Seibold, Götz A1 - Krebs, Andreas T1 - Excitations in disordered superconductors: Inclusion of long-range Coulomb interactions Y1 - 2019 UR - https://www.hlrn.de/HLRN-Report-2019.pdf SN - 978-3-00-063360-7 SP - 269 PB - HLRN CY - Berlin ER -