@misc{XuHarlander, author = {Xu, Wenchao and Harlander, Uwe}, title = {Mean flow generation in rotating annulus with stochastic methods}, series = {17th European Turbulence Conference, ETC 2019, September 3 - 6, 2019, Torino, Italy}, journal = {17th European Turbulence Conference, ETC 2019, September 3 - 6, 2019, Torino, Italy}, address = {Turin}, pages = {1}, language = {en} } @misc{BorciaBorciaRichteretal., author = {Borcia, Ion-Dan and Borcia, Rodica and Richter, Sebastian and Xu, Wenchao and Bestehorn, Michael and Harlander, Uwe}, title = {Horizontal Faraday instability in a circular channel}, series = {Proceedings in Applied Mathematics and Mechanics (PAMM)}, volume = {19}, journal = {Proceedings in Applied Mathematics and Mechanics (PAMM)}, number = {1}, issn = {1617-7061}, doi = {10.1002/pamm.201900242}, pages = {2}, abstract = {We study surface waves in a circular channel placed on a rotating table. The tank can rotate with constant velocity and/or can oscillate. For a glycerin-water-solution with high viscosity, oscillation amplitudes about 20 cm and frequencies of 0.5 Hz, we observe surface patterns generated by a parametric instability. The circular geometry of the channel assures in a natural way the periodic lateral boundary conditions often used in the numerical simulations. Up to our knowledge this is the first experiment which evidences the horizontal Faraday instability in a container without walls blocking the flow in the oscillation direction. Experimental and numerical results are compared and discussed.}, language = {en} } @misc{BorciaBorciaXuetal., author = {Borcia, Ion-Dan and Borcia, Rodica and Xu, Wenchao and Bestehorn, Michael and Richter, Sebastian and Harlander, Uwe}, title = {Undular bores in a large circular channel}, series = {European Journal of Mechanics - B/Fluids}, volume = {79}, journal = {European Journal of Mechanics - B/Fluids}, issn = {0997-7546}, doi = {10.1016/j.euromechflu.2019.09.003}, pages = {67 -- 73}, abstract = {An experimental device previously developed for studying rotating baroclinic flows has been used to investigate undular bores formation, propagation and collision. Up to our knowledge this is the first experimental study of undular bores in a circular channel. For a setup without barriers, this geometry accomplishes in a natural way the periodic lateral boundary conditions, very often used in numerical simulations. An excellent agreement between the experiment and simulation has been achieved. The spatio-temporal structure of bores is well reproduced for the first few reflections or collisions.}, language = {en} } @misc{KurganskySeeligKleinetal., author = {Kurgansky, Michael V. and Seelig, Torsten and Klein, Marten and Will, Andreas and Harlander, Uwe}, title = {Mean flow generation due to longitudinal librations of sidewalls of a rotating annulus}, series = {Geophysical \& Astrophysical Fluid Dynamics}, volume = {114}, journal = {Geophysical \& Astrophysical Fluid Dynamics}, number = {6}, issn = {1029-0419}, doi = {10.1080/03091929.2019.1692829}, pages = {762}, abstract = {Laboratory experiments with a rotating cylindrical annulus arereported that reveal a prograde jet, which is adjacent to a (longitu-dinally) librating inner straight cylindrical wall. Here, wall libration isrealised as a time-harmonic modulation of the inner cylinder's rota-tion rate. The outer cylindrical wall and bottom and top lids rotatewith constant angular velocity. The main purpose of our study is tocontribute to a qualitative and quantitative understanding of non-linearities that are present in oscillating, but centrifugally stable,vertical boundary layers frequently encountered in rotating wall-bounded flows. We consider a problem that is in a sense comple-mentary to that of previous works that focused on oscillating Ekmanlayers but neglected the vertical Stokes-Stewartson layers. A sim-ple analytical model is proposed that is able to predict the magni-tude and spatial structure of the emerging prograde near-wall jet interms of nonlinearity inherent in the inner cylinder's boundary layerdynamics.}, 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{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{Harlander, author = {Harlander, Uwe}, title = {Comparison of paradigmatic gravity wave models for ocean and atmosphere}, series = {EGU General Assembly 2020, Online | 4-8 May 2020}, journal = {EGU General Assembly 2020, Online | 4-8 May 2020}, doi = {10.5194/egusphere-egu2020-7222}, language = {en} } @misc{VinczeBozokiHereinetal., author = {Vincze, Miklos and Boz{\´o}ki, Tam{\´a}s and Herein, M{\´a}ty{\´a}s and Borcia, Ion-Dan and Rodda, Costanza and P{\´a}lfy, J{\´o}zsef and Nyerges, Anita and Harlander, Uwe}, title = {Climate impact of the Drake Passage opening: lessons from a minimalistic laboratory experiment}, series = {EGU General Assembly 2020, Online | 4-8 May 2020}, journal = {EGU General Assembly 2020, Online | 4-8 May 2020}, doi = {10.5194/egusphere-egu2020-5004}, language = {en} } @misc{FruehSzaboEgbersetal., author = {Fr{\"u}h, Wolf-Gerrit and Szabo, Peter and Egbers, Christoph and Harlander, Uwe}, title = {Locating sources of variability in the transition to Structural Vacillation in the baroclinic annulus}, series = {EGU General Assembly 2020, Online | 4-8 May 2020}, journal = {EGU General Assembly 2020, Online | 4-8 May 2020}, doi = {10.5194/egusphere-egu2020-7262}, language = {en} } @misc{HarlanderHenseWilletal., author = {Harlander, Uwe and Hense, Andreas and Will, Andreas and Kurgansky, Michael V.}, title = {New aspects of geophysical fluid dynamics}, series = {Meteorologische Zeitschrift}, volume = {15}, journal = {Meteorologische Zeitschrift}, number = {4}, doi = {10.1127/0941-2948/2006/0144}, pages = {388}, language = {en} } @misc{RoddaHarlanderSavaroetal., author = {Rodda, Costanza and Harlander, Uwe and Savaro, C. and Campagne, A. and Calpe Linares, M. and Augier, P. and Sommeria, Joel and Valran, T. and Viboud, Samuel and Mordant, N.}, title = {Can Laboratory experiments help to explain the atmosphere and ocean's energetics?}, series = {Colaborative Research Center TRR 181, Energy transfers in Atmosphere and Oceans, 16th - 18th Mar. 2021, Universit{\"a}t Hamburg, Center for Earth System Research and Sustainability (CEN)}, journal = {Colaborative Research Center TRR 181, Energy transfers in Atmosphere and Oceans, 16th - 18th Mar. 2021, Universit{\"a}t Hamburg, Center for Earth System Research and Sustainability (CEN)}, language = {en} } @misc{VinczeBozokiHereinetal., author = {Vincze, Miklos and Boz{\´o}ki, Tam{\´a}s and Herein, M{\´a}ty{\´a}s and Borcia, Ion-Dan and Harlander, Uwe and Horics{\´a}nyi, Attila and Nyerges, Anita and Rodda, Costanza and P{\´a}l, Andr{\´a}s and P{\´a}lfy, J{\´o}zsef}, title = {The Drake Passage opening from an experimental fluid dynamics point of view}, series = {SScientific Reports}, volume = {11}, journal = {SScientific Reports}, issn = {2045-2322}, doi = {10.1038/s41598-021-99123-0}, pages = {11}, 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} } @misc{HarlanderKurgansky, author = {Harlander, Uwe and Kurgansky, Michael V.}, title = {Two-dimensional internal gravity wave beam instability. Linear theory and subcritical instability}, series = {Geophysical \& Astrophysical Fluid Dynamics}, journal = {Geophysical \& Astrophysical Fluid Dynamics}, issn = {1029-0419}, doi = {10.1080/03091929.2021.1943379}, language = {en} } @misc{LeGalHarlanderBorciaetal., author = {Le Gal, Patrice and Harlander, Uwe and Borcia, Ion-Dan and Le Diz{\`e}s, St{\´e}phane and Chen, J. and Favier, Benjamin}, title = {Instability of vertically stratified horizontal plane Poiseuille flow}, series = {Journal of Fluid Mechanics}, volume = {907}, journal = {Journal of Fluid Mechanics}, number = {R1}, issn = {1469-7645}, doi = {10.1017/jfm.2020.917}, pages = {1 -- 14}, language = {en} } @misc{HarlanderBorciaVinczeetal., author = {Harlander, Uwe and Borcia, Ion-Dan and Vincze, Miklos and Rodda, Costanza}, title = {Probability Distribution of Extreme Events in a Baroclinic Wave Laboratory Experiment}, series = {Fluids}, volume = {7}, journal = {Fluids}, number = {8}, issn = {2311-5521}, doi = {10.3390/fluids7080274}, abstract = {Atmospheric westerly jet streams are driven by temperature differences between low and high latitudes and the rotation of the Earth. Meandering jet streams and propagating Rossby waves are responsible for the variable weather in the mid-latitudes. Moreover, extreme weather events such as heat waves and cold spells are part of the jet stream dynamics. For many years, a simple analog in the form of a simplified laboratory experiment, the differentially heated rotating annulus, has provided insight into the dynamics of the meandering jet stream. In the present study, probability density distributions of extreme events from a long-term laboratory experiment are studied and compared to the atmospheric probability density distributions. Empirical distributions of extreme value monthly block data are derived for the experimental and atmospheric cases. Generalized extreme value distributions are adjusted to the empirical distributions, and the distribution parameters are compared. Good agreement was found, but the distributions of the experimental data showed a shift toward larger extreme values, and some explanations for this shift are suggested. The results indicate that the laboratory model might be a useful tool for investigating changes in extreme event distributions due to climate change. In the laboratory context, the change can be modeled by an increase in total temperature accompanied by a reduction in the radial heat contrast.}, language = {en} } @misc{RoddaHarlanderVincze, author = {Rodda, Costanza and Harlander, Uwe and Vincze, Miklos}, title = {Jet stream variability in a polar warming scenario - a laboratory perspective}, series = {Weather and Climate Dynamics}, volume = {3}, journal = {Weather and Climate Dynamics}, number = {3}, issn = {2698-4016}, doi = {10.5194/wcd-3-937-2022}, pages = {937 -- 950}, language = {en} } @misc{BorciaRichterBorciaetal., author = {Borcia, Ion-Dan and Richter, Sebastian and Borcia, Rodica and Sch{\"o}n, Franz-Theo and Harlander, Uwe and Bestehorn, Michael}, title = {Wave propagation in a circular channel: sloshing and resonance}, series = {The European Physical Journal Special Topics}, volume = {Vol. 232}, journal = {The European Physical Journal Special Topics}, number = {4}, issn = {1951-6401}, doi = {10.1140/epjs/s11734-023-00790-z}, pages = {461 -- 468}, abstract = {Surface wave resonance of a liquid (water) layer confined in a circular channel is studied both experimentally and numerically. For the experiment, eight unevenly distributed ultrasonic distance sensors measure the local height of the wave surface. The resonance curves show maxima only for odd multiples of the fundamental resonance frequency . We explained this behavior using a simple intuitive "ping-pong" like model. Collision of wave fronts can be observed for higher frequencies. Also, the wave reflection on the walls can be treated as wave collision with itself. The non-linearity seems to be weak in our study so the delay in the wave propagation before and after the collision is small. Time-space plots show localized propagating waves with high amplitudes for frequencies near resonance. Between the peaks low amplitude and harmonic patterns are observed. However, for higher frequencies, the frequency band for localized waves becomes wider. In the Fourier space-time plane, this can be observed as a point for the harmonic patterns or a superposition of two lines: one line parallel to wave-vector k axis corresponding to the excitation frequency and a second line with inclination given by wave propagation velocity . For planned future work, this result will help us to reconstruct the whole water surface elevation using time-series from only a few measurement points}, language = {en} } @misc{LabarbeLeGalHarlanderetal., author = {Labarbe, Joris and Le Gal, Patrice and Harlander, Uwe and Le Diz{\`e}s, St{\´e}phane and Favier, Benjamin}, title = {Localized layers of turbulence in stratified horizontally sheared Poiseuille flow}, series = {Fluid Dynamics}, journal = {Fluid Dynamics}, pages = {20}, language = {en} } @misc{HarlanderSukhanovskiiAbideetal., author = {Harlander, Uwe and Sukhanovskii, Andrei and Abide, St{\´e}phane and Borcia, Ion-Dan and Popova, Elene and Rodda, Costanza and Vasiliev, Andrei and Vincze, Miklos}, title = {New Laboratory Experiments to Study the Large-Scale Circulation and Climate Dynamics}, series = {Atmosphere}, volume = {14}, journal = {Atmosphere}, number = {5}, doi = {10.3390/atmos14050836}, pages = {19}, abstract = {The large-scale flows of the oceans and the atmosphere are driven by a non-uniform surface heating over latitude, and rotation. For many years scientists try to understand these flows by doing laboratory experiments. In the present paper we discuss two rather new laboratory experiments designed to study certain aspects of the atmospheric circulation. One of the experiments, the differentially heated rotating annulus at the Brandenburg University of Technology (BTU) Cottbus, has a cooled inner cylinder and a heated outer wall. However, the structure of the atmospheric meridional circulation motivates a variation of this "classical" design. In the second experiment described, operational at the Institute of Continuous Media Mechanics (ICMM) in Perm, heating and cooling is performed at different vertical levels that resembles more the atmospheric situation. Recent results of both experiments are presented and discussed. Differences and consistencies are highlighted. Though many issues are still open we conclude that both setups have their merits. The variation with heating and cooling at different levels might be more suited to study processes in the transition zone between pure rotating convection and the zone of westerly winds. On the other hand, the simpler boundary conditions of the BTU experiment make this experiment easier to control.}, language = {en} } @misc{MalteseMelettideOliveiraAbideViazzoetal., author = {Maltese Meletti de Oliveira, Gabriel and Abide, St{\´e}phane and Viazzo, Stephane and Harlander, Uwe}, title = {A parameter study of strato-rotational low-frequency modulations: impacts on momentum transfer and energy distribution}, series = {Philosophical transactions of the Royal Society : Series A, Mathematical, physical and engineering sciences}, volume = {381}, journal = {Philosophical transactions of the Royal Society : Series A, Mathematical, physical and engineering sciences}, number = {2246}, issn = {1364-503X}, doi = {10.1098/rsta.2022.0297}, language = {en} } @misc{VinczeHancockHarlanderetal., author = {Vincze, Miklos and Hancock, Cathrine and Harlander, Uwe and Rodda, Costanza and Speer, Kevin}, title = {Extreme temperature fluctuations in laboratory models of the mid-latitude atmospheric circulation}, series = {Scientific reports}, volume = {13 (2023)}, journal = {Scientific reports}, doi = {10.1038/s41598-023-47724-2}, pages = {13}, language = {en} } @misc{HarlanderKurganskySpeeretal., author = {Harlander, Uwe and Kurgansky, Michael V. and Speer, Kevin and Vincze, Miklos}, title = {Baroclinic instability from an experimental perspective}, series = {Comptes Rendus Physique}, volume = {25 (2024)}, journal = {Comptes Rendus Physique}, doi = {10.5802/crphys.198}, pages = {1 -- 48}, language = {en} } @misc{SchoenHarlanderBorciaetal., author = {Sch{\"o}n, Franz-Theo and Harlander, Uwe and Borcia, Ion Dan and Borcia, Rodica and Bestehorn, Michael}, title = {Mean fluid transport in an oscillating circular channel with asymmetric forcing}, series = {Water waves : an interdisciplinary journal}, volume = {2025}, journal = {Water waves : an interdisciplinary journal}, publisher = {Birkh{\"a}user, part of Springer Nature}, address = {Basel}, issn = {2523-3688}, doi = {10.1007/s42286-025-00121-w}, pages = {1 -- 21}, abstract = {We investigate surface waves in an oscillating circular channel with local topography. The focus is on spatially or temporally breaking this dynamic system's symmetry. Asymmetrical wave dynamics and a mean flux excitation are detected to varying degrees, depending on the two input parameters, fluid depth and the tank's oscillation frequency. The fluid resonates around multiples of the fundamental eigenfrequency of the channel. The development of solitary wave-trains (undular bores) is observed in these resonance bands. A particle image velocimetry system measures the velocity field in the vertical plane of the free surface flow. Moreover, we are using 17 evenly distributed ultrasonic sensors to measure the surface displacement. This makes it possible to find out how strongly the mean flux depends on the resonance frequencies and to study the influence of the surface waves on the symmetry breaking. A numerical long-wave model helps to isolate the various factors influencing the mean flux.}, language = {en} } @misc{MelettiAbideHarlanderetal., author = {Meletti, Gabriel and Abide, St{\´e}phane and Harlander, Uwe and Raspo, Isabelle and St{\´e}phane Viazzo, St{\´e}phane}, title = {On the influence of the heat transfer at the free surface of a thermally driven rotating annulus}, series = {Physics of fluids}, volume = {37}, journal = {Physics of fluids}, publisher = {AIP Publishing}, address = {College Park, MD}, issn = {1089-7666}, doi = {10.1063/5.0248712}, pages = {1 -- 16}, abstract = {Experiments on rotating annuli that are differentially heated in the radial direction have largely contributed to a better understanding of baroclinic instabilities. This configuration creates waves at a laboratory scale that are related to atmospheric circulations. Pioneer studies in baroclinic tanks have shown that experiments with low aspect ratios are more suitable to reproduce small-scale inertia gravity waves, but these tanks have a larger free surface, which leads to higher interactions with their surrounding environment. Considering the heat transferred through the free surface, the present work investigates its impacts on the baroclinic instability using direct numerical simulations (DNS).}, language = {en} }