@misc{YoshikawaKangMutabazietal., author = {Yoshikawa, Harunori and Kang, Changwoo and Mutabazi, Innocent and Zaussinger, Florian and Haun, Peter and Egbers, Christoph}, title = {Thermoelectrohydrodynamic convection in parallel plate capacitors under dielectric heating conditions}, series = {Physical review fluids}, volume = {5}, journal = {Physical review fluids}, number = {11}, issn = {2469-990X}, doi = {10.1103/PhysRevFluids.5.113503}, pages = {17}, language = {en} } @misc{HasanuzzamanMerboldCuvieretal., author = {Hasanuzzaman, Gazi and Merbold, Sebastian and Cuvier, Christophe and Motuz, Vasyl and Foucaut, Jean-Marc and Egbers, Christoph}, title = {Experimental investigation of turbulent boundary layers at high Reynolds number with uniform blowing, part I: statistics}, series = {Journal of Turbulence}, journal = {Journal of Turbulence}, number = {3}, issn = {1468-5248}, doi = {10.1080/14685248.2020.1740239}, pages = {129 -- 165}, abstract = {Uniform blowing in wall bounded shear flows is well known for its drag reducing effects and has long been investigated ever since. However, many contemporary and former research on this topic has confirmed the drag reducing effect but very less is known regarding how blowing is effecting the Reynolds stresses at high Reynolds number. Therefore, effect of uniform blowing has been experimentally investigated using Stereo Particle Image Velocimetry (SPIV) measurements in a zero pressure gradient turbulent boundary layer (TBL). The data presented in this literature covers a large range of high Reynolds number flow e.g. Reθ = 7500∼19763 where Reynolds number is based on the momentum thickness. Upstream blowing was varied from 1\%∼6\% of free stream velocity and measurements were taken downstream after a short interval. Logarithmic and outer region of the TBL was given special attention in terms of investigating statistics and turbulence properties.}, language = {en} } @misc{XuHarlander, author = {Xu, Wenchao and Harlander, Uwe}, title = {Inertial mode interactions in a rotating tilted cylindrical annulus with free surface}, series = {Physical Review Fluids}, volume = {5}, journal = {Physical Review Fluids}, number = {9}, issn = {2469-990X}, doi = {10.1103/PhysRevFluids.5.094801}, pages = {21}, language = {en} } @misc{ZaussingerHaunSzaboetal., author = {Zaussinger, Florian and Haun, Peter and Szabo, Peter and Travnikov, Vadim and Al-Kawwas, Mustafa and Egbers, Christoph}, title = {Rotating spherical gap convection in the GeoFlow International Space Station (ISS) experiment}, series = {Physical Review Fluids}, volume = {5}, journal = {Physical Review Fluids}, number = {6}, issn = {2469-990X}, doi = {10.1103/PhysRevFluids.5.063502}, pages = {23}, language = {en} } @misc{TravnikovZaussingerHaunetal., author = {Travnikov, Vadim and Zaussinger, Florian and Haun, Peter and Egbers, Christoph}, title = {Influence of dielectrical heating on convective flow in a radial force field}, series = {Physical Review E}, volume = {101}, journal = {Physical Review E}, number = {5}, issn = {2470-0053}, doi = {10.1103/PhysRevE.101.053106}, pages = {16}, language = {en} } @misc{RoddaHarlander, author = {Rodda, Costanza and Harlander, Uwe}, title = {Transition from Geostrophic Flows to Inertia-Gravity Waves in the Spectrum of a Differentially Heated Rotating Annulus Experiment}, series = {Journal of the Atmospheric Sciences}, volume = {77}, journal = {Journal of the Atmospheric Sciences}, number = {8}, issn = {1520-0469}, doi = {10.1175/JAS-D-20-0033.1}, pages = {2793 -- 2806}, language = {en} } @misc{GhasemiKleinHarlanderetal., author = {Ghasemi, Abouzar and Klein, Marten and Harlander, Uwe and Kurgansky, Michael V. and Schaller, Eberhard and Will, Andreas}, title = {Mean flow generation by G{\"o}rtler vortices in a rotating annulus with librating side walls}, series = {Physics of Fluids}, volume = {28}, journal = {Physics of Fluids}, number = {056603}, doi = {10.1063/1.4948406}, pages = {1 -- 23}, abstract = {Time periodic variation of the rotation rate of an annulus induces in supercritical regime an unstable Stokes boundary layer over the cylinder side walls, generating G{\"o}rtler vortices in a portion of a libration cycle as a discrete event. Numerical results show that these vortices propagate into the fluid bulk and generate an azimuthal mean flow. Direct numerical simulations of the fluid flow in an annular container with librating outer (inner) cylinder side wall and Reynolds-averaged Navier-Stokes (RANS) equations as diagnostic equations are used to investigate generation mechanism of the retrograde (prograde) azimuthal mean flow in the bulk. First, we explain, phenomenologically, how absolute angular momentum of the bulk flow is mixed and changed due to the propagation of the G{\"o}rtler vortices, causing a new vortex of basin size. Then we investigate the RANS equations for intermediate time scale of the development of the G{\"o}rtler vortices and for long time scale of the order of several libration periods. The former exhibits sign selection of the azimuthal mean flow. Investigating the latter, we predict that the azimuthal mean flow is proportional to the libration amplitude squared and to the inverse square root of the Ekman number and libration frequency and then confirms this using the numerical data. Additionally, presence of an upscale cascade of energy is shown, using the kinetic energy budget of fluctuating flow.}, language = {en} } @misc{FuttererDahleyEgbers, author = {Futterer, Birgit and Dahley, Norman and Egbers, Christoph}, title = {Thermal electro-hydrodynamic heat transfer augmentation in vertical annuli by the use of dielectrophoretic forces through a.c. electric field}, series = {International Journal of Heat and Mass Transfer}, volume = {93}, journal = {International Journal of Heat and Mass Transfer}, issn = {0017-9310}, pages = {144 -- 154}, language = {en} } @misc{GrimmStreleKupkaLoewBasellietal., author = {Grimm-Strele, Hannes and Kupka, Friedrich and L{\"o}w-Baselli, Bernhard and Mundprecht, Eva and Zaussinger, Florian and Schiansky, Peter}, title = {Realistic simulations of stellar surface convection with ANTARES: I. Boundary conditions and model relaxation}, series = {New Astronomy}, volume = {34}, journal = {New Astronomy}, issn = {1384-1076}, doi = {10.1016/j.newast.2013.11.005}, pages = {278 -- 293}, language = {en} } @misc{FuttererDahleyEgbers, author = {Futterer, Birgit and Dahley, Norman and Egbers, Christoph}, title = {Thermal electro-hydrodynamic heat transfer augmentation in vertical annuli by the use of dielectrophoretic forces through a.c. electric field}, series = {International Journal of Heat and Mass Transfer}, volume = {vol. 93}, journal = {International Journal of Heat and Mass Transfer}, doi = {doi:10.1016/j.ijheatmasstransfer.2015.10.005}, pages = {144 -- 154}, language = {en} } @misc{VinczeHarlanderLarcheretal., author = {Vincze, Miklos and Harlander, Uwe and Larcher, Thomas von and Egbers, Christoph}, title = {An experimental study of regime transitions in a differentially heated baroclinic annulus with flat and sloping bottom topographies}, series = {Nonlinear Processes in Geophysics}, volume = {21}, journal = {Nonlinear Processes in Geophysics}, number = {1}, issn = {1607-7946}, doi = {10.5194/npg-21-237-2014}, pages = {237 -- 250}, 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} } @misc{SeeligHarlander, author = {Seelig, Torsten and Harlander, Uwe}, title = {Can zonally symmetric inertial waves drive an oscillating zonal mean flow?}, series = {Geophysical \& Astrophysical Fluid Dynamics}, volume = {109}, journal = {Geophysical \& Astrophysical Fluid Dynamics}, number = {6}, issn = {1029-0419}, doi = {10.1080/03091929.2015.1094064}, pages = {541 -- 566}, language = {en} } @misc{HoffHarlanderEgbers, author = {Hoff, Michael and Harlander, Uwe and Egbers, Christoph}, title = {Empirical singular vectors of baroclinic flows deduced from experimental data of a differentially heated rotating annulus}, series = {Meteorologische Zeitschrift}, volume = {23}, journal = {Meteorologische Zeitschrift}, number = {6}, doi = {10.1127/metz/2014/0563}, pages = {581 -- 597}, language = {en} } @incollection{HarlanderLarcherWrightetal., author = {Harlander, Uwe and Larcher, Thomas von and Wright, G. B. and Hoff, Michael and Alexandrov, Kiril and Egbers, Christoph}, title = {Orthogonal decomposition methods to analyze PIV, LDV and thermography data of a thermally driven rotating annulus laboratory experiment}, series = {Modeling Atmospheric and Oceanic Flows: Insights from Laboratory Experiments and Numerical Simulations}, booktitle = {Modeling Atmospheric and Oceanic Flows: Insights from Laboratory Experiments and Numerical Simulations}, editor = {Larcher, Thomas von and Williams, Paul D.}, publisher = {Wiley}, address = {Hoboken}, isbn = {978-1-118-85593-5}, doi = {10.1002/9781118856024}, pages = {315 -- 336}, language = {en} } @misc{KoenigZanounOengueneretal., author = {K{\"o}nig, Franziska and Zanoun, El-Sayed and {\"O}ng{\"u}ner, Emir and Egbers, Christoph}, title = {The CoLaPipe - The new Cottbus large pipe test facility at Brandenburg University of Technology Cottbus-Senftenberg}, series = {Review of scientific instruments}, volume = {85}, journal = {Review of scientific instruments}, number = {7}, issn = {1089-7623}, doi = {10.1063/1.4884717}, pages = {075115-1 -- 075115-9}, language = {en} } @phdthesis{Butt, author = {Butt, Usman}, title = {Experimental investigation of the flow over macroscopic hexagonal structured surfaces}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-30555}, language = {en} } @misc{ButtJehringEgbers, author = {Butt, Usman and Jehring, Lothar and Egbers, Christoph}, title = {Mechanism of drag reduction for circular cylinders with patterned surface}, series = {International journal of heat and fluid flow}, volume = {Vol. 45}, journal = {International journal of heat and fluid flow}, issn = {1879-2278}, pages = {128 -- 134}, language = {en} } @misc{FuttererEgbers, author = {Futterer, Birgit and Egbers, Christoph}, title = {Der innere Kreislauf der Erde : geophysikalisches Str{\"o}mungsexperiment auf der ISS}, series = {Physik in unserer Zeit}, volume = {45}, journal = {Physik in unserer Zeit}, number = {3}, isbn = {1521-3943}, pages = {126 -- 131}, language = {de} } @phdthesis{Dahley, author = {Dahley, Norman}, title = {Dielectrophoretic flow control of thermal convection in cylindrical geometries}, publisher = {Cuvillier}, address = {G{\"o}ttingen}, isbn = {978-3-95404-863-2}, pages = {IX, 171}, language = {en} }