@inproceedings{KleinBorciaEgbersetal., author = {Klein, Marten and Borcia, Ion-Dan and Egbers, Christoph and Ghasemi, Abouzar and Harlander, Uwe and Kurgansky, Michael V. and Schaller, Eberhard and Seelig, Torsten and Will, Andreas}, title = {Inertial Waves and Wave Excitation Mechanisms in Annular Cavities: Simulations, Experiments and Theory}, series = {European Turbulence Conference ETC14, Lyon, 2013}, booktitle = {European Turbulence Conference ETC14, Lyon, 2013}, pages = {2}, language = {en} } @inproceedings{KleinGhasemiHarlanderetal., author = {Klein, Marten and Ghasemi, Abouzar and Harlander, Uwe and Will, Andreas}, title = {Inertial wave excitation and wave attractors in a librating annulus: DNS}, series = {European Geosciences Union, General Assembly 2014, Vienna, Austria, 27 April - 02 May 2014}, booktitle = {European Geosciences Union, General Assembly 2014, Vienna, Austria, 27 April - 02 May 2014}, publisher = {European Geophysical Society}, address = {Katlenburg-Lindau}, language = {en} } @inproceedings{KleinGhasemiSeeligetal., author = {Klein, Marten and Ghasemi, Abouzar and Seelig, Torsten and Borcia, Ion-Dan and Harlander, Uwe and Will, Andreas}, title = {DNS of inertial wave attractors in a librating annular cavity with a height-dependent gap}, series = {ICTW 19, Book of Abstracts, 19th International Couette-Taylor Workshop, June 24 - 26, 2015 Cottbus, Germany}, booktitle = {ICTW 19, Book of Abstracts, 19th International Couette-Taylor Workshop, June 24 - 26, 2015 Cottbus, Germany}, address = {Cottbus}, pages = {122 -- 123}, language = {en} } @misc{KleinSeeligKurganskyetal., author = {Klein, Marten and Seelig, Torsten and Kurgansky, Michael V. and Ghasemi, Abouzar and Borcia, Ion-Dan and Will, Andreas and Schaller, Eberhard and Egbers, Christoph and Harlander, Uwe}, title = {Inertial wave excitation and focusing in a liquid bounded by a frustum and a cylinder}, series = {Journal of Fluid Mechanics}, journal = {Journal of Fluid Mechanics}, number = {vol. 751}, issn = {1750-6859}, doi = {10.1017/jfm.2014.304}, pages = {255 -- 297}, abstract = {The mechanism of localized inertial wave excitation and its efficiency is investigated for an annular cavity rotating with Ω0 . Meridional symmetry is broken by replacing the inner cylinder with a truncated cone (frustum). Waves are excited by individual longitudinal libration of the walls. The geometry is non-separable and exhibits wave focusing and wave attractors. We investigated laboratory and numerical results for the Ekman number E ≈ 10-6. inclination α = 5.71◦ and libration amplitudes ε 0.2 within the inertial wave band 0 < ω < 2Ω0 . Under the assumption that the inertial waves do not essentially affect the boundary-layer structure, we use classical boundary-layer analysis to study oscillating Ekman layers over a librating wall that is at an angle α = 0 to the axis of rotation. The Ekman layer erupts at frequency ω = f∗, where f∗ ≡ 2Ω0 sin α is the effective Coriolis parameter in a plane tangential to the wall. For the selected inclination this eruption occurs for the forcing frequency ω/Ω0 = 0.2. For the librating lids eruption occurs at ω/Ω0 = 2. The study reveals that the frequency dependence of the total kinetic energy Kω of the excited wave field is strongly connected to the square of the Ekman pumping velocity wE (ω) that, in the linear limit, becomes singular when the boundary layer erupts. This explains the frequency dependence of non-resonantly excited waves. By the localization of the forcing, the two configurations investigated, (i) frustum libration and (ii) lids together with outer cylinder in libration, can be clearly distinguished by their response spectra. Good agreement was found for the spatial structure of low-order wave attractors and periodic orbits (both characterized by a small number of reflections) in the frequency windows predicted by geometric ray tracing. For 'resonant' frequencies a significantly increased total bulk energy was found, while the energy in the boundary layer remained nearly constant. Inertial wave energy enters the bulk flow via corner beams, which are parallel to the characteristics of the underlying Poincar{\´e} problem. Numerical simulations revealed a mismatch between the wall-parallel mass fluxes near the corners. This leads to boundary-layer eruption and the generation of inertial waves in the corners.}, language = {en} }