TY - GEN A1 - Vincze, Miklos A1 - Harlander, Uwe A1 - Larcher, Thomas von A1 - Egbers, Christoph T1 - An experimental study of regime transitions in a differentially heated baroclinic annulus with flat and sloping bottom topographies T2 - Nonlinear Processes in Geophysics Y1 - 2014 U6 - https://doi.org/10.5194/npg-21-237-2014 SN - 1607-7946 VL - 21 IS - 1 SP - 237 EP - 250 ER - TY - GEN A1 - Klein, Marten A1 - Seelig, Torsten A1 - Kurgansky, Michael V. A1 - Ghasemi, Abouzar A1 - Borcia, Ion-Dan A1 - Will, Andreas A1 - Schaller, Eberhard A1 - Egbers, Christoph A1 - Harlander, Uwe T1 - Inertial wave excitation and focusing in a liquid bounded by a frustum and a cylinder T2 - Journal of Fluid Mechanics N2 - 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 Poincaré 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. KW - boundary-layer structure KW - geophysical and geological flows KW - waves in rotating fluids Y1 - 2014 U6 - https://doi.org/10.1017/jfm.2014.304 SN - 1750-6859 IS - vol. 751 SP - 255 EP - 297 ER - TY - GEN A1 - König, Franziska A1 - Zanoun, El-Sayed A1 - Öngüner, Emir A1 - Egbers, Christoph T1 - The CoLaPipe - The new Cottbus large pipe test facility at Brandenburg University of Technology Cottbus-Senftenberg T2 - Review of scientific instruments Y1 - 2014 U6 - https://doi.org/10.1063/1.4884717 SN - 1089-7623 VL - 85 IS - 7 SP - 075115-1 EP - 075115-9 ER - TY - THES A1 - Butt, Usman T1 - Experimental investigation of the flow over macroscopic hexagonal structured surfaces Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus4-30555 UR - http://opus4.kobv.de/opus4-btu/frontdoor/index/index/docId/3055 ER - TY - THES A1 - Dahley, Norman T1 - Dielectrophoretic flow control of thermal convection in cylindrical geometries Y1 - 2014 SN - 978-3-95404-863-2 PB - Cuvillier CY - Göttingen ER - TY - CHAP A1 - Harlander, Uwe A1 - Larcher, Thomas von A1 - Wright, G. B. A1 - Hoff, Michael A1 - Alexandrov, Kiril A1 - Egbers, Christoph ED - Larcher, Thomas von ED - Williams, Paul D. T1 - Orthogonal decomposition methods to analyze PIV, LDV and thermography data of a thermally driven rotating annulus laboratory experiment T2 - Modeling Atmospheric and Oceanic Flows: Insights from Laboratory Experiments and Numerical Simulations Y1 - 2014 SN - 978-1-118-85593-5 SN - 978-1-118-85590-4 U6 - https://doi.org/10.1002/9781118856024 SP - 315 EP - 336 PB - Wiley CY - Hoboken ER - TY - CHAP A1 - Öngüner, Emir A1 - Zanoun, El-Sayed A1 - Egbers, Christoph T1 - Turbulent Pipe Flow Structure Analysis in CoLa-Pipe T2 - Book of abstracts, 85th Annual Meeting of the International Association of Applied Mathematics and Mechanics, March 10 - 14, 2014, Erlangen Y1 - 2014 SP - S. 493 PB - Gesellschaft für Angewandte Mathematik und Mechanik ER - TY - CHAP A1 - Zanoun, El-Sayed A1 - König, Franziska A1 - Al-Mutairi, Fahad M. A1 - Egbers, Christoph A1 - Öngüner, Emir T1 - On the Application of Hot Wires and Pitot Tubes in Pipe and Channel Flows T2 - HEFAT 2014, 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, 6 – 9 July 2014 Orlando, Florida Y1 - 2014 U6 - https://doi.org/10.13140/2.1.3766.7521 ER - TY - CHAP A1 - Öngüner, Emir A1 - König, Franziska A1 - Zanoun, El-Sayed A1 - Egbers, Christoph T1 - Experimentelle Untersuchung der turbulenten Rohrstrukturen bei hohen Reynolds Zahlen T2 - GALA - Fachtagung Lasermethoden in der Strömungsmesstechnik, 22. Fachtagung, 9. - 11. September 2014, Karlsruhe Y1 - 2014 SN - 978-3-9816764-0-2 SP - S. 24 PB - GALA CY - Karlsruhe ER - TY - GEN A1 - Butt, Usman A1 - Jehring, Lothar A1 - Egbers, Christoph T1 - Mechanism of drag reduction for circular cylinders with patterned surface T2 - International journal of heat and fluid flow Y1 - 2014 SN - 1879-2278 VL - Vol. 45 SP - 128 EP - 134 ER - TY - GEN A1 - Futterer, Birgit A1 - Egbers, Christoph T1 - Der innere Kreislauf der Erde : geophysikalisches Strömungsexperiment auf der ISS T2 - Physik in unserer Zeit Y1 - 2014 SN - 1521-3943 VL - 45 IS - 3 SP - 126 EP - 131 ER - TY - THES A1 - Seelig, Torsten T1 - Inertial wave propagation, focusing and mean flow excitation : theory and experiments Y1 - 2014 SN - 978-3-95404-793-2 SN - 978-3-7369-4793-1 PB - Cuvillier CY - Göttingen ER -