TY - GEN A1 - Borcia, Ion-Dan A1 - Richter, Sebastian A1 - Borcia, Rodica A1 - Schön, Franz-Theo A1 - Harlander, Uwe A1 - Bestehorn, Michael T1 - Wave propagation in a circular channel: sloshing and resonance T2 - The European Physical Journal Special Topics N2 - 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 Y1 - 2023 UR - https://link.springer.com/article/10.1140/epjs/s11734-023-00790-z U6 - https://doi.org/10.1140/epjs/s11734-023-00790-z SN - 1951-6401 SN - 1951-6355 VL - Vol. 232 IS - 4 SP - 461 EP - 468 ER - TY - GEN A1 - Labarbe, Joris A1 - Le Gal, Patrice A1 - Harlander, Uwe A1 - Le Dizès, Stéphane A1 - Favier, Benjamin T1 - Localized layers of turbulence in stratified horizontally sheared Poiseuille flow T2 - Fluid Dynamics Y1 - 2023 UR - https://arxiv.org/abs/2207.09131 ER - TY - GEN A1 - Harlander, Uwe A1 - Sukhanovskii, Andrei A1 - Abide, Stéphane A1 - Borcia, Ion-Dan A1 - Popova, Elene A1 - Rodda, Costanza A1 - Vasiliev, Andrei A1 - Vincze, Miklos T1 - New Laboratory Experiments to Study the Large-Scale Circulation and Climate Dynamics T2 - Atmosphere N2 - 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. Y1 - 2023 UR - https://www.mdpi.com/2073-4433/14/5/836 U6 - https://doi.org/10.3390/atmos14050836 VL - 14 IS - 5 ER - TY - GEN A1 - Maltese Meletti de Oliveira, Gabriel A1 - Abide, Stéphane A1 - Viazzo, Stephane A1 - Harlander, Uwe T1 - A parameter study of strato-rotational low-frequency modulations: impacts on momentum transfer and energy distribution T2 - Philosophical transactions of the Royal Society : Series A, Mathematical, physical and engineering sciences Y1 - 2023 U6 - https://doi.org/10.1098/rsta.2022.0297 SN - 1364-503X SN - 1471-2962 VL - 381 IS - 2246 ER - TY - GEN A1 - Vincze, Miklos A1 - Hancock, Cathrine A1 - Harlander, Uwe A1 - Rodda, Costanza A1 - Speer, Kevin T1 - Extreme temperature fluctuations in laboratory models of the mid-latitude atmospheric circulation T2 - Scientific reports Y1 - 2023 U6 - https://doi.org/10.1038/s41598-023-47724-2 VL - 13 (2023) ER - TY - GEN A1 - Harlander, Uwe A1 - Kurgansky, Michael V. A1 - Speer, Kevin A1 - Vincze, Miklos T1 - Baroclinic instability from an experimental perspective T2 - Comptes Rendus Physique Y1 - 2024 U6 - https://doi.org/10.5802/crphys.198 VL - 25 (2024) SP - 1 EP - 48 ER - TY - GEN A1 - Schön, Franz-Theo A1 - Harlander, Uwe A1 - Borcia, Ion Dan A1 - Borcia, Rodica A1 - Bestehorn, Michael T1 - Mean fluid transport in an oscillating circular channel with asymmetric forcing T2 - Water waves : an interdisciplinary journal N2 - 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. Y1 - 2025 U6 - https://doi.org/10.1007/s42286-025-00121-w SN - 2523-3688 VL - 2025 SP - 1 EP - 21 PB - Birkhäuser, part of Springer Nature CY - Basel ER - TY - GEN A1 - Meletti, Gabriel A1 - Abide, Stéphane A1 - Harlander, Uwe A1 - Raspo, Isabelle A1 - Stéphane Viazzo, Stéphane T1 - On the influence of the heat transfer at the free surface of a thermally driven rotating annulus T2 - Physics of fluids N2 - 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). Y1 - 2025 U6 - https://doi.org/10.1063/5.0248712 SN - 1089-7666 VL - 37 SP - 1 EP - 16 PB - AIP Publishing CY - College Park, MD ER -