TY - JOUR A1 - Sitte, B. A1 - Brasch, W. A1 - Junk, M. A1 - Travnikov, Vadim A1 - Egbers, Christoph T1 - Thermal flow in a rotating spherical gap with a dielectrophoretic central force field Y1 - 2001 ER - TY - CHAP A1 - Travnikov, Vadim A1 - Egbers, Christoph A1 - Hollerbach, Rainer T1 - Thermische Konvektion im Kugelspalt unter radialem Kraftfeld: Dreidimensionale Stömung Y1 - 2004 ER - TY - GEN A1 - Meyer, Antoine A1 - Meier, Martin A1 - Motuz, Vasyl A1 - Egbers, Christoph T1 - Thermo-electric convection in a cylindrical annulus during a sounding rocket flight T2 - Journal of Fluid Mechanics Y1 - 2023 U6 - https://doi.org/10.1017/jfm.2023.677 SN - 0022-1120 VL - 972 IS - A26 ER - TY - GEN A1 - Meyer, Antoine A1 - Seelig, Torsten A1 - Meier, Martin A1 - Mutabazi, Innocent A1 - Egbers, Christoph T1 - Thermo-electro-hydrodynamic instability of a dielectric fluid in a vertical cylindrical annulus: Earth's gravity and weightless conditions T2 - 26th European Low Gravity Research Association Biennial Symposium and General Assembly, Granada (Spanien), September 24-27, 2019 Y1 - 2019 UR - https://www-docs.b-tu.de/fg-aerodynamik-stroemungslehre/public/PDF/Pubs/ELGRA2019_Book-of-abstracts.pdf SP - 115 EP - 116 ER - TY - GEN A1 - Meyer, Antoine A1 - Seelig, Torsten A1 - Gerstner, Philipp A1 - Kang, Changwoo A1 - Meier, Martin A1 - Jongmanns, Marcel A1 - Baumann, Martin A1 - Mutabazi, Innocent A1 - Heuveline, Vincent A1 - Egbers, Christoph T1 - Thermo-electro-hydrodynamic instability of a dielectric fluid in a vertical cylindrical annulus: Earth’s gravity and weightless conditions T2 - LIA-ISTROF workshop 2019 Instabilities and Turbulence in Stratified Rotational Flows Cottbus, 19th-20th June 2019 Brandenburg Y1 - 2019 UR - https://www-docs.b-tu.de/fg-aerodynamik-stroemungslehre/public/PDF/Pubs/ELGRA2019_Book-of-abstracts.pdf CY - Cottbus ER - TY - GEN A1 - Szabo, Peter A1 - Gaillard, Yann A1 - Egbers, Christoph T1 - Thermo-electrohydrodynamic (TEHD) convection in rotating spherical gap: A 2D-numerical simulation of the AtmoFlow sphere T2 - European Fluid Mechanics Conference EFMC14 Y1 - 2022 UR - https://www.erasmus.gr/microsites/1240/scientific-programme SP - 37 ER - TY - CHAP A1 - Strangfeld, Matthias A1 - Bölük, Oguzhan A1 - Szabo, Peter A1 - Meier, Martin A1 - Meyer, Antoine A1 - Sliavin, Yaraslau A1 - Motuz, Vasyl A1 - Egbers, Christoph T1 - Thermo-electrohydrodynamic convection in a dielectric fluid layer with volumetric heating T2 - GALA-Fachtagung "Experimentelle Strömungsmechanik", 6.- 8. September 2022, Ilmenau Y1 - 2022 UR - https://www.researchgate.net/publication/363615870_Thermo-electrohydrodynamic_convection_in_a_dielectric_fluid_layer_with_volumetric_heating SP - 43.1 EP - 43.8 ER - TY - GEN A1 - Szabo, Peter A1 - Gaillard, Yann A1 - Zaussinger, Florian A1 - Egbers, Christoph T1 - Thermo-electrohydrodynamic convection in a differentially heated shell with electric central force field T2 - Proceedings in applied mathematics and mechanics : PAMM Y1 - 2023 U6 - https://doi.org/10.1002/pamm.202200121 SN - 1617-7061 N1 - 92nd Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM) VL - 23 IS - 1 ER - TY - GEN A1 - Gaillard, Yann A1 - Szabo, Peter A1 - Travnikov, Vadim A1 - Egbers, Christoph T1 - Thermo-electrohydrodynamic convection in a rotating shell with central force field T2 - International Journal of Heat and Mass Transfer Y1 - 2024 U6 - https://doi.org/10.1016/j.ijheatmasstransfer.2023.124760 SN - 0017-9310 VL - Vol. 2018 SP - 1 EP - 12 ER - TY - GEN A1 - Kabat, Nancy A1 - Jende, Enrico A1 - Yücel, Fatma Cansu A1 - Stathopoulos, Panagiotis T1 - Thermodynamic analysis of a novel high-temperature heat pump cycle configuration based on the reversed Brayton cycle T2 - International journal of sustainable energy N2 - High-temperature heat pumps offer a promising approach to deliver CO$_2$-neutral process heat by upgrading waste heat with electricity from renewable resources. In this work, a heat pump configuration including multiple heat sinks and sources is presented and compared to the recuperated Brayton cycle. An exergy analysis is conducted by using numerical simulations to provide process heat at 250°C and process cooling at -30°C simultaneously. The results show, that a multi-stage compression leads to an improved overall performance for simultaneous heating and cooling. A parametric study presents the influence of the isentropic efficiency, heat exchanger effectiveness and heat sink and source inlet temperature on the second law efficiency. This study serves as a basis to gain a better understanding on the physics of the novel cycle, highlighting the potentials of improving the efficiency of Brayton heat pumps with cycle layouts adaptation and identify the most important components for minimizing exergy losses. Y1 - 2025 SN - 1478-6451 VL - 44 IS - 1 SP - 1 EP - 37 PB - Taylor & Francis CY - Abingdon, Oxon ER - TY - GEN A1 - Kabat, Nancy A1 - Jende, Enrico A1 - Yücel, Fatma Cansu A1 - Stathopoulos, Panagiotis T1 - Thermodynamic analysis of a novel high-temperature heat pump cycle with inter cooled compression and reheated expansion based on the reversed Brayton cycle T2 - International journal of sustainable energy N2 - High temperature heat pumps offer a promising approach to deliver CO2-neutral process heat by upgrading waste heat with electricity from renewable resources. In this work, a heat pump cycle including inter cooled compression and reheated expansion is presented and compared to the simple Brayton cycle. Numerical simulations are used to investigate the provision of process heat at 250°C and process cooling at -30°C. An exergy analysis and parameter study is carried out. The results show an improved performance of the complex cycle as a result of more efficient temperature profiles improving the exergy utilisation. While previous studies often consider idealised process variants or are focused on individual purposes, the present work contributes to the analysis and evaluation of complex cycles with multi-stage process control while simultaneously supplying heat and cold. A deeper understanding of the thermodynamic interactions provides a reliable basis for the energy-related design of systems with multiple temperature levels. KW - High-temperature heat pump KW - Brayton cycle KW - Inter cooled compression KW - Reheated expansion KW - Exergy analysis KW - Parametric study Y1 - 2025 U6 - https://doi.org/10.1080/14786451.2025.2515452 SN - 1478-6451 VL - 44 IS - 1 SP - 1 EP - 37 PB - Taylor & Francis CY - Abingdon, Oxon ER - TY - GEN A1 - Vankelekom, Christophe A1 - Stathopoulos, Panagiotis A1 - Demeyer, Frederiek A1 - De Paepe, Ward ED - Vankelekom, Christophe T1 - Thermodynamic performance assessment of recuperated Brayton cycle high-temperature heat pumps for combined heat and cold roduction T2 - Proceedings of ASME Turbo Expo 2025 : Turbomachinery Technical Conference and Exposition, June 16-20, 2025, Memphis, Tennessee : Volume 4 : Controls, Diagnostics & Instrumentation; Cycle Innovations; Education; Electric Power N2 - Producing heat at high temperatures for industrial processes like chemistry, food, or paper is still achieved using fossil fuels. To reach net-zero CO2 emissions by 2050, as desired by the European Union, technology driven by renewable energy must emerge to electrify these sectors. For this reason, high-temperature heat pumps, based on a Reversed Brayton Cycle working with air, offer a promising solution. Indeed, nowadays, most high-temperature heat pumps are vapor compression cycles but they face several issues when a higher temperature is necessary (200 °C or more). The selection of refrigerant is challenging (high compression ratio and temperature limitation), and it has a non-negligible environmental impact. Nevertheless, the Reversed Brayton cycle still suffers from a low Coefficient Of Performance (COP) that could be improved by valorizing the cold heat flux produced in the cycle. In the literature, few works are related to this combined use of heating and cooling for sub-MWth applications, which is very important for the food industry (cooking and freezing). With this work, we aim to fill this gap by proposing an analysis of the achievable potential based on the 2nd law of thermodynamics using a generic model in Aspen Plus. Using a heat sink of 250 °C and 300 °C and a heat source of −10 °C, the potential of different cycles were analyzed by varying the secondary inlet temperature of the heat sink from 100 °C to 200 °C. For low inlet temperatures, the heating and total COP can reach a value of up to 1.3 and 1.66 respectively with an exergetic efficiency up to 54%. The COP decreases when the secondary inlet temperature of the heat sink increases while the exergy efficiency stays almost constant. A further increase does not allow to provide cooling anymore for lower outlet heat sink temperature. KW - High-temperature heat pumps KW - Heating and cooling KW - Reversed Brayton cycle KW - Exergy analysis Y1 - 2025 SN - 978-0-7918-8880-3 U6 - https://doi.org/10.1115/GT2025-153988 PB - American Society of Mechanical Engineers CY - New York, NY ER - TY - GEN A1 - Barry, Elhadj A1 - Yoshikawa, Harunori A1 - Kang, Changwoo A1 - Meyer, Antoine A1 - Meier, Martin A1 - Crumeyrolle, Olivier A1 - Egbers, Christoph A1 - Mutabazi, Innocent T1 - Thermoelectric convection in a planar capacitor: theoretical studies and experiments in parabolic flights T2 - Comptes Rendus Mécanique Y1 - 2023 UR - https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.5802/crmeca.143/ SN - 1873-7234 SP - 1 EP - 15 ER - TY - CHAP A1 - Mutabazi, Innocent A1 - Kang, Changwoo A1 - Meyer, Antoine A1 - Jongmanns, Marcel A1 - Meier, Martin A1 - Egbers, Christoph T1 - Thermoelectric convection in dielectric liquids in a cylindrical annulus T2 - International Conference on Rayleigh Bénard Turbulence, May 14-18, 2018, Enschede, NL Y1 - 2018 UR - https://pof.tnw.utwente.nl/rbc2018/wp-content/uploads/2018/05/RBC2018_abstract_booklet.pdf SP - S. 83 ER - TY - GEN A1 - Meyer, Antoine A1 - Yoshikawa, Harunori A1 - Szabo, Peter A1 - Meier, Martin A1 - Egbers, Christoph A1 - Mutabazi, Innocent T1 - Thermoelectric instabilities in a circular Couette flow T2 - Philosophical transactions of the Royal Society. Series A, Mathematical, physical and engineering sciences Y1 - 2023 U6 - https://doi.org/10.1098/rsta.2022.0139 SN - 1471-2962 SN - 1364-503X VL - 381 IS - 2243 ER - TY - GEN A1 - Meyer, Antoine A1 - Seelig, Torsten A1 - Gerstner, Philipp A1 - Kang, Changwoo A1 - Meier, Martin A1 - Jongmanns, Marcel A1 - Baumann, Martin A1 - Mutabazi, Innocent A1 - Heuveline, Vincent A1 - Egbers, Christoph T1 - Thermoelectric instability in a vertical cylindrical annulus T2 - 8th International Symposium on Bifurcations and Instabilities in Fluid Dynamics (BIFD), 16-19 July, 2019, University of Limerick, Ireland Y1 - 2019 CY - Limerick ER - TY - GEN A1 - Meyer, Antoine A1 - Meier, M. A1 - Szabo, Peter A1 - Sliavin, Yaraslau A1 - Motuz, Vasyl A1 - Gerstner, Philipp A1 - Roller, Jonas A1 - Heuveline, Vincent A1 - Egbers, Christoph T1 - Thermoelectric instability of a dielectric fluid in a cylindrical annulus with vertical or horizontal orientation T2 - European Fluid Mechanics Conference EFMC14 Y1 - 2022 UR - https://www.erasmus.gr/microsites/1240/scientific-programme SP - 37 ER - TY - GEN A1 - Yoshikawa, Harunori A1 - Kang, Changwoo A1 - Mutabazi, Innocent A1 - Zaussinger, Florian A1 - Haun, Peter A1 - Egbers, Christoph T1 - Thermoelectrohydrodynamic convection in parallel plate capacitors under dielectric heating conditions T2 - Physical review fluids Y1 - 2020 U6 - https://doi.org/10.1103/PhysRevFluids.5.113503 SN - 2469-990X VL - 5 IS - 11 ER - TY - CHAP A1 - Jongmanns, Marcel A1 - Seelig, Torsten A1 - Egbers, Christoph A1 - Meier, Martin A1 - Meyer, Antoine A1 - Crumeyrolle, Olivier A1 - Mutabazi, Innocent T1 - Thermoelectrohydrodynamic experiments in a cylindrical gap T2 - Book of abstracts, School ISTROF 2016, Instabilities and Turbulence in Strato-Rotational Flows, July 11-13th, 2016, Le Havre Y1 - 2016 UR - https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxzY2hvb2xpc3Ryb2Z8Z3g6NDA3Y2E3ZGQ2OWIwMTdmNQ ER - TY - GEN A1 - Zanoun, El-Sayed A1 - Jehring, Lothar A1 - Egbers, Christoph T1 - Three measuring techniques for assessing the mean wall skin friction in wall-bounded flows T2 - Thermophysics and Aeromechanics Y1 - 2014 SN - 1531-8699 SN - 0869-8643 VL - 21 IS - 2 SP - 179 EP - 190 ER - TY - CHAP A1 - Scurtu, Nicoleta A1 - Futterer, Birgit A1 - Egbers, Christoph T1 - Three-dimensional natural Convection in spherical annuli Y1 - 2007 ER - TY - JOUR A1 - Scurtu, Nicoleta A1 - Futterer, Birgit A1 - Egbers, Christoph T1 - Three-dimensional natural Convection in spherical annuli Y1 - 2008 ER - TY - CHAP A1 - Harlander, Uwe A1 - Maas, L. R. M. T1 - Tide-topography interactions? Y1 - 2011 ER - TY - CHAP A1 - Beltrame, Philippe A1 - Egbers, Christoph A1 - Travnikov, Vadim T1 - Time-dependent dynamics in the "GEOFLOW" experiment on the ISS Y1 - 2004 ER - TY - GEN A1 - Hallol, Zeinab A1 - Yousry, Mohamed A1 - Merbold, Sebastian A1 - Egbers, Christoph T1 - Time-resolved PIV measurements in fully developed turbulent pipe flow T2 - 25th International Congress of Theoretical and Applied Mechanics Milan (Italy), 22-27 August 2021 Y1 - 2021 UR - https://iutam.org/publications/ictam-proceedings/ictam_2020/ SN - 978-83-65550-31-6 SP - 1374 EP - 1375 ER - TY - CHAP A1 - Merbold, Sebastian A1 - Froitzheim, Andreas A1 - Egbers, Christoph ED - Kähler, Christian J. ED - Hain, Rainer ED - Scharnowski, Sven ED - Fuchs, Thomas T1 - Torque in turbulent Taylor-Couette flow for small radius ratios T2 - Proceedings of the 5th International Conference on Experimental Fluid Mechanics, Munich 2018 Y1 - 2018 SN - 978-3-943207-32-3 U6 - https://doi.org/10.18726/2018_2 SP - 598 EP - 602 PB - Institute of Fluid Mechanics and Aerodynamics, Universität der Bundeswehr CY - Neubiberg ER - TY - CHAP A1 - Froitzheim, Andreas A1 - Merbold, Sebastian A1 - Egbers, Christoph T1 - Torque measurements and flow visualization in a wide gap Taylor-Couette Flow T2 - 15th European turbulence conference (ETC), Delft, The Netherlands (2015) Y1 - 2015 UR - http://www.etc15.nl/proceedings/proceedings/documents/262.pdf ER - TY - GEN A1 - Merbold, Sebastian A1 - Brauckmann, Hannes A1 - Egbers, Christoph T1 - Torque measurements and numerical determination in differentially rotating wide gap Taylor-Couette flow T2 - Physical Review E Y1 - 2013 U6 - https://doi.org/10.1103/PhysRevE.87.023014 SN - 1550-2376 VL - 87 IS - 2 SP - 023014 -1 EP - 023014 -4 ER - TY - CHAP A1 - Froitzheim, Andreas A1 - Merbold, Sebastian A1 - Egbers, Christoph T1 - Torque measurements in a Taylor-Couette experiment with very small radius ration of 0.357 T2 - 16th European Turbulence Conference, 21-24 August, 2017, Stockholm, Sweden Y1 - 2017 UR - http://www.delegia.com/app/data/8684/Abstract/28671/ETC16_Froitzheim.pdf ER - TY - CHAP A1 - Merbold, Sebastian A1 - Egbers, Christoph T1 - Torque measurements in a wide gap Taylor-Couette flow T2 - 14th European Turbulence Conference, Lyon, France, September 1-4, 2013 Y1 - 2013 UR - http://etc14.ens-lyon.fr/etc-14-proceedings/accepted-talks/ ER - TY - GEN A1 - Merbold, Sebastian A1 - Fischer, Steffen A1 - Egbers, Christoph T1 - Torque scaling in Taylor-Couette-Flow - An experimental investigation Y1 - 2011 ER - TY - JOUR A1 - Harlander, Uwe T1 - Towards an analytical understanding of internal wave attractors Y1 - 2008 ER - TY - GEN A1 - Shahirpour, Amir A1 - Herzog, Nicoleta A1 - Egbers, Christoph T1 - Towards CFD Modeling of Carbon Dioxide Turbulent Pipe Line Transportation T2 - Energy Procedia Y1 - 2013 UR - http://www.sciencedirect.com/science/article/pii/S187661021301641X UR - 1876-6102 U6 - https://doi.org/10.1016/j.egypro.2013.08.047 VL - 40 SP - 408 EP - 417 ER - TY - CHAP A1 - Shahirpour, Amir A1 - Herzog, Nicoleta A1 - Egbers, Christoph T1 - Towards CFD modeling of turbulent pipeline material transportation T2 - European Geosciences Union (EGU), 10th General Assembly, Vienna, Austria, 07 – 12 April 2013 Y1 - 2013 UR - http://meetingorganizer.copernicus.org/EGU2013/EGU2013-5893.pdf N1 - EGU2013-5893 ER - TY - GEN A1 - Rodda, Costanza A1 - Harlander, Uwe T1 - Transition from Geostrophic Flows to Inertia–Gravity Waves in the Spectrum of a Differentially Heated Rotating Annulus Experiment T2 - Journal of the Atmospheric Sciences Y1 - 2020 U6 - https://doi.org/10.1175/JAS-D-20-0033.1 SN - 1520-0469 SN - 0022-4928 VL - 77 IS - 8 SP - 2793 EP - 2806 ER - TY - GEN A1 - Hamede, Mohammed Hussein A1 - Merbold, Sebastian A1 - Egbers, Christoph T1 - Transition to the ultimate turbulent regime in a very wide gap Taylor-Couette flow (η = 0.1) with a stationary outer cylinder T2 - EPL (Europhysics Letters) Y1 - 2023 U6 - https://doi.org/10.1209/0295-5075/acdea1 SN - 1286-4854 VL - 143 IS - 2 ER - TY - CHAP A1 - Merbold, Sebastian A1 - Kumar, Chandana B.V. A1 - Egbers, Christoph T1 - Transparent water tunnel for educational purpose of fundamental flow phenomena and Laser-optical measurement techniques T2 - Experimentelle Strömungsmechanik : 29. Fachtagung, 6.-8. September 2022, Ilmenau T2 - Transparenter Wasserkanal zum Lehrzweck grundlegendener Strömungsphänome und Laser-optischen Messtechniken Y1 - 2022 UR - https://www.gala-ev.org/images/Beitraege/Beitraege2022/pdf/53.pdf SN - 978-3-9816764-8-8 PB - Deutsche Gesellschaft für Laser-Anemometrie - German Association for Laser Anemometry GALA e.V. CY - Karlsruhe ER - TY - THES A1 - Schön, Franz-Theo T1 - Transport and waves in parametrically excited fluid layers N2 - The transport and waves in parametrically excited fluid layers play a significant role in an understanding of non-linear surface wave phenomena and tidal resonances. In this thesis, we study resonant waves occurring in a circular channel with various obstacles under external oscillatory excitation. Typically, such sloshing experiments are conducted in rectangular, straight channels. The external excitation is implemented using a rotating table on which the entire experiment, including measurement equipment, is mounted. The excitation is either sinusoidal or ratched motion. The obstacles include a fully blocking barrier and a symmetric or asymmetric hill. The channel circumference is 4.76 m, with water depths ranging from 2 cm to 6 cm. Wave displacements within the channel are measured using 17 ultrasonic sensors equidistantly distributed along half of the channel. Particle Image Velocimetry (PIV) is employed to measure the flow. We also consider a simplified numerical model capable of reproducing the experimental results. This model is based on a long-wave approximation and vertical integration using a profile function (Kármán-Pohlhausen approach). Additionally, we use a wave attractor model to quantitatively explain the development of resonances. These resonances are distributed in bands of the excitation frequency around the linear eigenfrequency. The experimental wave attractor and numerical results are consistent with each other. The waves observed within these resonant frequency bands appear as undular bores or solitary waves. In the fully blocking case, bands of constructive and destructive interference are observed, while in the presence of hills, all eigenfrequencies exhibit resonances of varying intensity. These non-linear wave phenomena are characterized by strong transport properties, which can be studied here due to the fact that the circular channel is not fully blocked. The ratched excitation generated asymmetric wave fields, which also induced asymmetric transport in the channel, leading to the emergence of a mean flow in the channel. A similar mean channel flow is observed for the asymmetric hill; however, wave-induced transport played a lesser role in this case. This is attributed to a large separation vortex on the steep side of the hill, which created a valve effect that rectified part of the oscillatory flow. These results are of interest not only for engineering applications but also for the understanding of tidal flows over seabed topography. N2 - Der Transport und die Wellen in parametrisch angeregten Flüssigkeitsschichten spielt eine große Rolle im Verständnis von nichtlinearen Oberflächenwellenphänomenen und Gezeitenresonanzen. In dieser Arbeit werden resonante Wellen untersucht, die in einem kreisförmigen Kanal mit verschiedenen Hindernissen auftreten, wenn dieser einer externen oszillatorischen Anregung ausgesetzt wird. Normalerweise werden solche Schwapp-Experimente in rechteckigen, geraden Kanälen durchgeführt. Die externe Anregung wird durch einen Rotationstisch realisiert, auf dem sich das gesamte Experiment inklusive Messtechnik befindet. Die Anregung erfolgt entweder sinusoidal oder sägezahnförmig. Die Hindernisse sind eine völlig verschließende Barriere sowie ein symmetrischer oder asymmetrischer Berg. Der mittlere Kanalumfang hat eine Gesamtlänge von 4,76 m, während Wasserhöhen von 2 cm bis 6 cm untersucht werden. Als Messmethode für die Auslenkung der im Kanal befindlichen Wellen werden 17 Ultraschallsensoren verwendet, welche äquidistant über die Hälfte des Kanals verteilt sind. Zur Messung der Strömung wird Particle Image Velocimetry verwendet. Wir betrachten in dieser Arbeit ebenfalls ein vereinfachtes numerisches Modell, das in der Lage ist, die experimentellen Ergebnisse zu reproduzieren. Dieses Modell basiert auf einer Langwellennäherung und der vertikalen Integration über eine Profilfunktion (Kármán-Pohlhausen-Ansatz). Ein Wellenattraktor-Modell beschreibt die Entwicklung von Resonanzen qualitativ, die in Bändern der Anregungsfrequenz um die lineare Eigenfrequenz herum angeordnet sind. Die experimentellen Wellenattraktor- und numerischen Ergebnisse sind konsistent miteinander. Die Wellen, die innerhalb dieser resonanten Frequenzbänder beobachtet werden, treten als gewellter Schwall (undular bore) oder Einzelwelle (solitary wave) auf. Im vollständig blockierenden Fall werden Bänder konstruktiver und destruktiver Interferenz beobachtet, während im Fall der Berge alle Eigenfrequenzen Resonanzen unterschiedlicher Stärke aufweisen. Diese nichtlinearen Wellenphänomene zeichnen sich durch starke Transporteigenschaften aus, die wir hier aufgrund der Kreisförmigkeit des nicht komplett verschlossenen Kanals studieren können. Die sägezahnförmige Anregung erzeugt asymmetrische Wellenfelder, die ebenfalls einen asymmetrischen Transport im Kanal bewirkt, der zum Erscheinen einer Kanalmittelströmung führt. Eine ähnliche Kanalmittelströmung wird für den asymmetrischen Berg beobachtet, allerdings spielt der Transport durch Wellen hier eine untergeordnete Rolle. Dies liegt daran, dass eine große Ablöseblase an der steilen Bergseite einen Ventileffekt erzeugte, die einen Teil der oszillierenden Strömung gleichrichtete. Diese Ergebnisse sind nicht nur für ingenieurtechnische Anwendungen von Interesse, sondern auch für das Verständnis von Gezeitenströmen über Bodenformen. Y1 - 2025 U6 - https://doi.org/10.26127/BTUOpen-6995 PB - Brandenburgische Technische Universität CY - Cottbus ; Senftenberg ER - TY - GEN A1 - Futterer, Birgit A1 - Koch, Sandy A1 - Egbers, Christoph T1 - Traveling waves in low and intermediate rotating spherical shell convection Y1 - 2011 ER - TY - CHAP A1 - Motuz, Vasyl A1 - Kornilov, V. I. A1 - Jehring, Lothar A1 - Egbers, Christoph T1 - Turbulent Boundary Layer Over An Uniformly Perforated Surface With Blowing Y1 - 2011 ER - TY - CHAP A1 - Hasanuzzaman, Gazi A1 - Motuz, Vasyl A1 - Merbold, Sebastian A1 - Egbers, Christoph A1 - Cuvier, Christophe A1 - Foucaut, Jean-Marc T1 - Turbulent boundary layer statistics under the influence of uniform micro-blowing T2 - 16th European Turbulence Conference, 21-24 August, 2017, Stockholm, Sweden Y1 - 2017 UR - http://www.delegia.com/app/data/8684/Abstract/29581/ETC16_Hasanuzzaman.pdf ER - TY - CHAP A1 - Merbold, Sebastian A1 - Fischer, Steffen A1 - Egbers, Christoph T1 - Turbulent Couette-Taylor flow - An experimental investigation of the angular momentum flux Y1 - 2011 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 - Merbold, Sebastian A1 - Froitzheim, Andreas A1 - Egbers, Christoph T1 - Turbulent Taylor-Couette flow for very wide gaps T2 - ICTW 19, Book of Abstracts, 19th International Couette-Taylor Workshop, June 24 - 26, 2015 Cottbus, Germany Y1 - 2015 SP - 26 EP - 27 CY - Cottbus ER - TY - CHAP A1 - Motuz, Vasyl A1 - Jehring, Lothar A1 - Egbers, Christoph T1 - Turbulente Grenzschichtströmung an einer gleichmäßig perforierten Wand mit Mikro-Ausblasen T2 - Lasermethoden in der Strömungsmesstechnik, 20. Fachtagung, 04. - 06. September 2012, Rostock Y1 - 2012 SN - 978-3-9805613-8-9 PB - GALA CY - Karlsruhe ER - TY - GEN A1 - Harlander, Uwe A1 - Kurgansky, Michael V. T1 - Two-dimensional internal gravity wave beam instability. Linear theory and subcritical instability T2 - Geophysical & Astrophysical Fluid Dynamics Y1 - 2021 U6 - https://doi.org/10.1080/03091929.2021.1943379 SN - 1029-0419 SN - 0309-1929 ER - TY - GEN A1 - Zanoun, El-Sayed A1 - Egbers, Christoph A1 - Dewidar, Yasser T1 - Two-Point Velocity Correlations in Fully Developed Turbulent Pipe Flow at Shear Reynolds Number of Reτ ≈ 4000 T2 - Proceedings in Applied Mathematics and Mechanics : (PAMM) Y1 - 2021 U6 - https://doi.org/10.1002/pamm.202000330 SN - 1617-7061 VL - 20 IS - 1 ER - TY - GEN A1 - Borcia, Ion-Dan A1 - Borcia, Rodica A1 - Xu, Wenchao A1 - Bestehorn, Michael A1 - Richter, Sebastian A1 - Harlander, Uwe T1 - Undular bores in a large circular channel T2 - European Journal of Mechanics - B/Fluids N2 - 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. KW - Undular bores KW - Bore collision KW - Periodical boundary conditions Y1 - 2020 UR - https://www.sciencedirect.com/science/article/pii/S0997754619300706?via%3Dihub U6 - https://doi.org/10.1016/j.euromechflu.2019.09.003 SN - 0997-7546 VL - 79 SP - 67 EP - 73 ER - TY - CHAP A1 - Larcher, Thomas von A1 - Egbers, Christoph ED - Dopheide, Dietrich ED - Müller, Harald ED - Strunck, Volker ED - Ruck, Bodo ED - Leder, Alfred T1 - Untersuchung barokliner Instabilitäten mit LDA und Strömungsvisualisierung, in: Lasermethoden in der Strömungsmesstechnik, 11. Fachtagung Y1 - 2003 SN - 3-00-011903-5 ER - TY - CHAP A1 - Nobis, Matthias A1 - Reinke, Peter A1 - Schmidt, Marcus A1 - Redlich, Marcel A1 - Egbers, Christoph A1 - Herzog, Nicoleta A1 - Gorenz, Paul A1 - Christl, Andreas T1 - Untersuchung der instationären Gleitlagerströmung T2 - 21. GALA-Tagung 2013, Lasermethoden in der Strömungsmesstechnik, 03. - 05. September 2013, München Y1 - 2013 SN - 978-3-9805613-9-6 SP - 51.1 EP - 51.10 PB - Dt. Gesellschaft für Laser-Anemometrie CY - Karlsruhe ER - TY - CHAP A1 - Stücke, Peter A1 - Egbers, Christoph T1 - Untersuchung der Spülströmung in kleinen Zweitaktmotoren Y1 - 2004 ER - TY - JOUR A1 - Smieszek, Marlene A1 - Egbers, Christoph T1 - Untersuchung eines scherverdünnenden Fluids im Zylinderspalt Y1 - 2006 ER - TY - CHAP A1 - Smieszek, Marlene A1 - Egbers, Christoph T1 - Untersuchung eines scherverdünnenden Fluids im Zylinderspalt Y1 - 2006 ER - TY - CHAP A1 - Jehring, Lothar A1 - Zanoun, El-Sayed A1 - Egbers, Christoph T1 - Untersuchung von ebenen Wandgrenzschichten mit verschiedenen optischen Messverfahren, Fachtagung Y1 - 2007 ER - TY - CHAP A1 - Larcher, Thomas von A1 - Egbers, Christoph T1 - Untersuchung von Übergangszonen barokliner Wellen mit LDA und Strömungsvisualisierung Y1 - 2005 ER - TY - CHAP A1 - Motuz, Vasyl A1 - Egbers, Christoph A1 - Naebert, T. A1 - Rohden, Christoph von ED - Egbers, Christoph T1 - Untersuchungen zur Strömung in einer aerologischen Messkammer bei niedrigen Drücken T2 - Experimentelle Strömungsmechanik, 24. Fachtagung 6.-8. September 2016 Cottbus Y1 - 2016 SN - 978-3-9816764-2-6 SP - S. 36 PB - German Association for Laser Anemometry GALA e.V. CY - Karlsruhe ER - TY - CHAP A1 - Sliavin, Yaraslau A1 - Szabo, Peter A1 - Früh, Wolf-Gerrit A1 - Schulze, Björn A1 - Egbers, Christoph T1 - Utilizing infrared thermography to investigate baroclinic instability in the differentially heated rotating annulus T2 - GALA-Fachtagung "Experimentelle Strömungsmechanik", 6.- 8. September 2022, Ilmenau Y1 - 2022 UR - https://www.researchgate.net/publication/363896369_GALA_Conference_2022_06_-_0809_Utilizing_infrared_thermography_to_investigate_baroclinic_instability_in_the_differentially_heated_rotating_annulus U6 - https://doi.org/10.13140/RG.2.2.32413.59360 SP - 49.1 EP - 49.8 ER - TY - GEN A1 - Futterer, Birgit A1 - Zaussinger, Florian A1 - Egbers, Christoph A1 - Scurtu, Nicoleta T1 - Variation of viscosity contrast for convection experiments in spherical shells as part of geophy-sical flow simulation experiment "GeoFlow II" Y1 - 2011 ER - TY - GEN A1 - Froitzheim, Andreas A1 - Merbold, Sebastian A1 - Egbers, Christoph T1 - Velocity profiles, flow structures and scalings in a wide-gap turbulent Taylor-Couette flow T2 - Journal of Fluid Mechanics Y1 - 2017 U6 - https://doi.org/10.1017/jfm.2017.634 SN - 0022-112 SN - 1469-7645 VL - 831 SP - 330 EP - 357 ER - TY - CHAP A1 - Jehring, Lothar A1 - Zanoun, El-Sayed A1 - Kito, Mizuki T1 - Vermessung wandnaher Strömungen unter Verwendung eines neuartigen miniaturisierten Sensor-Moduls Y1 - 2005 ER - TY - CHAP A1 - Erdogdu, Ahmed Oguzhan A1 - Szabo, Peter A1 - Carter, R. A1 - Gevre, M.-E. A1 - Haun, Peter A1 - Zaussinger, Florian A1 - Schulze, B. A1 - Meier, Martin A1 - Egbers, Christoph T1 - Verwendung der Wollaston-Scherinterferometrie zur Untersuchung des Brechungsindexgradienten in einem differentiell beheizten Ringspalt T2 - Experimentelle Strömungsmechanik : 28. Fachtagung, 7.-9. September 2021, Bremen T2 - Utilizing Wollaston shearing interferometry to investigate the refractive index gradient in a differentially heated annulus Y1 - 2021 SN - 978-3-9816764-7-1 SP - 19 PB - Deutsche Gesellschaft für Laser-Anemometrie - German Association for Laser Anemometry GALA e.V. CY - Karlsruhe ER - TY - CHAP A1 - Herzog, Nicoleta T1 - Viscoelastic fluid instability in analogy with the magnetorotational instability in Taylor-Couette flows Y1 - 2011 ER - TY - CHAP A1 - Stücke, Peter A1 - Egbers, Christoph ED - Dopheide, Dietrich ED - Müller, Harald ED - Strunck, Volker ED - Ruck, Bodo ED - Leder, Alfred T1 - Visualisierung der Strömung im Inneren von Zylindern für kleine Zweitaktmotoren, in: Lasermethoden in der Strömungsmesstechnik, 11. Fachtagung Y1 - 2003 SN - 3-00-011903-5 ER - TY - JOUR A1 - Stücke, Peter A1 - Egbers, Christoph T1 - Visualization of scavenging flow in the design of small two-stroke engines Y1 - 2006 ER - TY - CHAP A1 - Stücke, Peter A1 - Egbers, Christoph A1 - Geyer, W. T1 - Visualization of the Scavenging Flow of Small Two-Stroke Cylinders Y1 - 2004 ER - TY - GEN A1 - Zanoun, El-Sayed A1 - Egbers, Christoph A1 - Nagib, H. M. A1 - Durst, F. A1 - Bellani, Gabriele A1 - Talamelli, Alessandro T1 - Wall friction relations in wall-bounded shear flows T2 - European Journal of Mechanics - B/Fluids Y1 - 2021 U6 - https://doi.org/10.1016/j.euromechflu.2021.03.007 SN - 1873-7390 SN - 0997-7546 VL - Vol. 89 SP - 171 EP - 179 ER - TY - CHAP A1 - Sevlam, Kamal A1 - Öngüner, Emir A1 - Peixinho, Jorge A1 - Zanoun, El-Sayed A1 - Egbers, Christoph T1 - Wall pressure fluctuations in developing turbulent pipe flow T2 - Book of abstracts, School ISTROF 2016, Instabilities and Turbulence in Strato-Rotational Flows, July 11-13th, 2016, Le Havre Y1 - 2016 UR - https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxzY2hvb2xpc3Ryb2Z8Z3g6NDA3Y2E3ZGQ2OWIwMTdmNQ ER - TY - GEN A1 - Selvam, Kamal A1 - Öngüner, Emir A1 - Peixinho, Jorge A1 - Zanoun, El-Sayed A1 - Egbers, Christoph T1 - Wall pressure in developing turbulent pipe flows T2 - Journal of Fluids Engineering Y1 - 2018 SN - 1528-901X SN - 0098-2202 VL - 140 IS - 8 ER - TY - GEN A1 - Zanoun, El-Sayed A1 - Durst, F. A1 - Saleh, O. A1 - Al-Salaymeh, Ahmed T1 - Wall skin friction and mean velocity profiles of fully developed turbulent pipe flows T2 - Experimental Thermal and Fluid Science Y1 - 2006 U6 - https://doi.org/10.1016/j.expthermflusci.2007.04.002 SN - 0894-1777 VL - 32 IS - 1 SP - 249 EP - 261 ER - TY - CHAP A1 - Öngüner, Emir A1 - Dittmar, Mirko A1 - Meyer, P. A1 - Zanoun, El-Sayed A1 - Egbers, Christoph T1 - Wall-bounded turbulent Structures in pipe flow based on streamwise and cross-sectional PIV at Re=10^4-10^5 T2 - 11th European Fluid Mechanics Conference, Sept. 12-16, 2016, Sevilla, Spain Y1 - 2016 UR - http://www.efmc11.org/download/com/com_0703_KFARSY.pdf ER - 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 - Koch, Sandy A1 - Harlander, Uwe A1 - Egbers, Christoph T1 - Wave-attractors and mean flow in a spherical shell due to time-modulated rotation Y1 - 2010 ER - TY - CHAP A1 - Öngüner, Emir A1 - Zanoun, El-Sayed A1 - Fiorini, Tommaso A1 - Bellani, Gabriele A1 - Shahirpour, Amir A1 - Egbers, Christoph A1 - Talamelli, Alessandro ED - Örlü, Ramis ED - Talamelli, Alessandro ED - Peinke, Joachim ED - Oberlack, Martin T1 - Wavenumber Dependence of Very Large-Scale Motions in CICLoPE at 4800 ≤ Reτ ≤ 37.000 T2 - Progress in Turbulence VII, Proceedings of the iTi Conference in Turbulence 2016 Y1 - 2017 UR - https://link.springer.com/chapter/10.1007/978-3-319-57934-4_15 SN - 978-3-319-57933-7 SP - 101 EP - 106 PB - Springer CY - Cham ER - TY - CHAP A1 - Koch, Sandy A1 - Harlander, Uwe A1 - Hollerbach, Rainer A1 - Rabitti, A. A1 - Maas, L. R. M. A1 - Egbers, Christoph T1 - Wellen und Wellenattrktoren in einer Kugelschale mit zeitlich modulierter Rotation Y1 - 2010 ER - TY - CHAP A1 - Froitzheim, Andreas A1 - Merbold, Sebastian A1 - Egbers, Christoph T1 - Wide gap Taylor-Couette flow T2 - ICTW 19, Book of Abstracts, 19th International Couette-Taylor Workshop, June 24 - 26, 2015 Cottbus, Germany Y1 - 2015 SP - 28 EP - 29 CY - Cottbus ER - TY - CHAP A1 - Seelig, Torsten A1 - Harlander, Uwe A1 - Borcia, Ion-Dan A1 - Egbers, Christoph T1 - Zonal mean flow excitation due to inertial waves propagating in the meridional plane T2 - European Geosciences Union (EGU), 9th General Assembly, Vienna, Austria, 22-27 April Y1 - 2012 UR - http://meetingorganizer.copernicus.org/EGU2012/EGU2012-4981-1.pdf N1 - EGU2012-4981-1 ER - TY - THES A1 - Larcher, Thomas von T1 - Zur Stabilität barokliner Wellen im starr rotierenden Zylinderspalt Y1 - 2007 SN - 3-18-348607-6 PB - VDI-Verl. CY - Düsseldorf ER - TY - JOUR A1 - Travnikov, Vadim A1 - Egbers, Christoph T1 - Zur Stabiliät thermischer Konvektion im Kugelspalt unter Erdbedingungen Energietheorie Y1 - 2001 ER - TY - CHAP A1 - Uhlig, Benedict A1 - Kirner, Claus A1 - Preuß, Ann-Christin A1 - Graf, Johann A1 - Neben, Matthias T1 - Öltransport durch die Kolbenringe T2 - Abschluss- und Zwischenberichte der Forschungsstellen, gehalten auf der Informationstagung der FVV am 29. September 2016 in Madgeburg Y1 - 2016 SP - 197 EP - 230 PB - FVV, Forschungsvereinigung Verbrennungskraftmaschinen CY - Frankfurt ER - TY - JOUR A1 - Stücke, Peter A1 - Schwarz, M. A1 - Scurtu, Nicoleta A1 - Egbers, Christoph T1 - Über die exzentrische Zylinderspaltströmung bei engen Spaltweiten Y1 - 2006 ER -