@inproceedings{SeeligHarlanderBorciaetal., author = {Seelig, Torsten and Harlander, Uwe and Borcia, Ion-Dan and Scurtu, Nicoleta and Egbers, Christoph and Klein, Marten and Ghasemi, Abouzar and Will, Andreas and Schaller, Eberhard}, title = {Inertial waves in rotating cylindrical annulus: theory, experiment and simulations}, series = {Book of abstracts, 9th European Fluid Mechanics Conference (EFMC), 9-13 September, Rome, Italy}, booktitle = {Book of abstracts, 9th European Fluid Mechanics Conference (EFMC), 9-13 September, Rome, Italy}, language = {en} } @inproceedings{KersteinGlaweSchmidtetal., author = {Kerstein, Alan R. and Glawe, Christoph and Schmidt, Heiko and Klein, Rupert and Gonzalez-Juez, Esteban D. and Schmidt, Rodney}, title = {Computational modeling of scalar transport and buoyancy effects in turbulent flows using ODTLES}, series = {Bulletin of the American Physical Society}, volume = {57}, booktitle = {Bulletin of the American Physical Society}, number = {17}, language = {en} } @inproceedings{GlaweKleinKersteinetal., author = {Glawe, Christoph and Klein, Rupert and Kerstein, Alan R. and Schmidt, Heiko}, title = {Towards the simulation of gravity waves using the One-Dimensional Turbulence model}, series = {EGU General Assembly 2012, held 22-27 April, 2012 in Vienna}, booktitle = {EGU General Assembly 2012, held 22-27 April, 2012 in Vienna}, language = {en} } @inproceedings{SeeligBorciaKleinetal., author = {Seelig, Torsten and Borcia, Ion-Dan and Klein, Marten and Ghasemi, Abouzar and Will, Andreas and Egbers, Christoph and Schaller, Eberhard and Harlander, Uwe}, title = {Inertial waves and wave attractors in a rotating annulus with inner or outer cylinder libration}, series = {European Geosciences Union (EGU), 10th General Assembly, Vienna, Austria, 07 - 12 April 2013}, booktitle = {European Geosciences Union (EGU), 10th General Assembly, Vienna, Austria, 07 - 12 April 2013}, language = {en} } @misc{GerlichOhsiekKleinetal., author = {Gerlich, Lukas and Ohsiek, Susanne and Klein, Christoph and Geiß, Mario and Friedemann, Michael and K{\"u}cher, Peter and Schmeißer, Dieter}, title = {Interface engineering for the TaN/Ta barrier film deposition process to control Ta-crystal growth}, series = {Microelectronic Engineering}, volume = {Vol. 106}, journal = {Microelectronic Engineering}, doi = {10.1016/j.mee.2013.01.017}, pages = {63 -- 68}, abstract = {As a consequence of device shrinking the resistivity of the widely used TaN/Ta double barrier layer becomes an increasingly important parameter for device speed beyond the 32 nm technology node. In this study we describe the optimization of the deposition of TaN/Ta stacks in such a way that tantalum nitride layer thickness is minimized and tantalum grows in the favorable conducting alpha-phase. In the first part of the study we usedin situ ARXPS to investigate the growth of different tantalum nitride layers on SiO2 and SiOCH as a function of deposition time, nitrogen flow and deposition power. In the second part we analyzed the crystalline phase of a 20 nm thick tantalum layer deposited on top of the same series of tantalum nitride layers characterized in the growth study. The main findings are the appearance of tan-talum carbide and tantalum silicide as interface species for the deposition on SiOCH and only tantalum silicide for the deposition on SiO2. We found that alpha-tantalum grows preferably on tantalum carbide and nitrogen rich intermediate layers whereas silicide at the interface promotes the growth of beta-tantalum. To verify these findings we studied two additional modifications of the interface. A lower bias power for a deposition of tantalum nitride on SiO2 was used to confirm the role of tantalum silicide and a thermal treatment of a thin tantalum layer on SiOCH was applied to confirm the role of tantalum carbide. Finally, the contact resistance in via chains on patterned wafers for four selected processes showed the same trends as the sheet resistance of the corresponding barrier films on blanket wafer experiments.}, 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} } @inproceedings{KleinBorciaEgbersetal., author = {Klein, Marten and Borcia, Ion-Dan and Egbers, Christoph and Ghasemi, Abouzar and Harlander, Uwe and Kurgansky, Michael V. and Schaller, Eberhard and Seelig, Torsten and Will, Andreas}, title = {Inertial Waves and Wave Excitation Mechanisms in Annular Cavities: Simulations, Experiments and Theory}, series = {European Turbulence Conference ETC14, Lyon, 2013}, booktitle = {European Turbulence Conference ETC14, Lyon, 2013}, pages = {2}, language = {en} } @misc{GlaweSchmidtKersteinetal., author = {Glawe, Christoph and Schmidt, Heiko and Kerstein, Alan R. and Klein, Rupert}, title = {XLES Part I: Introduction to Extended Large Eddy Simulation}, series = {arXiv.org}, journal = {arXiv.org}, pages = {38}, abstract = {Direct numerical simulation (DNS), mostly used in fundamental turbulence research, is limited to low turbulent intensities due the current and future computer resources. Standard turbulence models, like RaNS (Reynolds averaged Navier-Stokes) and LES (Large Eddy Simulation), are applied to flows in engineering, but they miss small scale effects, which are frequently of importance, see e.g. the whole area of reactive flows, flows with apparent Prandtl or Schmidt number effects, or even wall bounded flows. A recent alternative to these standard approaches is the one-dimensional turbulence (ODT) model, which is limited to 1D sub-domains. In two papers we will provide a generalized filter strategy, called XLES (extended LES), including a formal theory (part I) and one special approach in the XLES family of models, called ODTLES (in part II (see Glawe et al. (2015))). ODTLES uses an ODT sub-grid model to describe all turbulent scales not represented by XLES, which leaves the larger scales to be simulated in 3D. This allows a turbulence modeling approach with a 3D resolution mainly independent of the turbulent intensity. Thus ODTLES is able to compute highly turbulent flows in domains of moderate complexity affordably and including the full range of turbulent and diffusive scales. The convergence of XLES to DNS is shown and the unconventional XLES advection approach is investigated in basic numerical tests. In part II, highly turbulent channel and duct flow results are discussed and show the future potential of XLES and ODTLES.}, language = {en} } @misc{GlaweSchmidtKersteinetal., author = {Glawe, Christoph and Schmidt, Heiko and Kerstein, Alan R. and Klein, Rupert}, title = {XLES Part II: From Extended Large Eddy Simulation to ODTLES}, series = {arXiv.org}, journal = {arXiv.org}, pages = {41}, abstract = {In turbulence research and flow applications, turbulence models like RaNS (Reynolds averaged Navier-Stokes) models and LES (Large Eddy Simulation) are used. Both models filter the governing flow equations. Thus a scale separation approach is introduced for modeling purposes with the large scales simulated using a numerical scheme while smaller scales are assumed to be less important and might be modeled more or less easily. Unfortunately small scales are frequently of big importance, e.g. in reactive flows, wall bounded flows, or flows with significant Prandtl or Schmidt number effects. Recent alternatives to these standard models are the class of models based on the one-dimensional turbulence (ODT) idea, like ODTLES. The ability of ODT to capture highly turbulent flows (recently up to Reτ=6×105) allows ODTLES to realize 3D resolutions basically independent of the turbulent intensity. In two papers we provide a formal theory and application of an innovative modeling strategy for highly turbulent flows in domains of moderate complexity: In part I (see Glawe et al. (2015)) a new general filtering approach, called XLES (extended LES), is introduced. Contrary to LES, XLES is based on 2D filtering of the governing equations, whereby additional small scale terms are interpreted numerically. In this work a new ansatz for the ODTLES model is introduced as one special approach in the XLES family of models by incorporating the ODT model into XLES. The ODT model introduces microstructures not captured by the XLES filtered equations. To illustrate the ODTLES model capabilities, turbulent channel and duct flows up to friction Reynolds number Reτ=10000 are studied.}, language = {en} } @misc{WasmerKoebeAndresenetal., author = {Wasmer, Kristina and K{\"o}be, Julia and Andresen, Dietrich and Zahn, Ralf and Spitzer, Stefan G. and Jehle, Joachim and Brachmann, Johannes and Stellbrink, Christoph and Martens, Eimo and Hochadel, Matthias and Senges, Jochen and Klein, Helmut and Eckhardt, Lars}, title = {Comparing outcome of patients with coronary artery disease and dilated cardiomyopathy in ICD and CRT recipients: data from the German DEVICE—registry}, series = {Clinical Research in Cardiology}, volume = {102}, journal = {Clinical Research in Cardiology}, number = {7}, issn = {1861-0684}, doi = {10.1007/s00392-013-0559-0}, pages = {513 -- 521}, language = {en} } @misc{BochAllanBirkhoferetal., author = {Boch, Steffen and Allan, Eric and Birkhofer, Klaus and Bossdorf, Oliver and Bl{\"u}thgen, Nico and Christ-Breulmann, Sabina and Diek{\"o}tter, Tim and Dormann, Carsten F. and Gossner, Martin M. and Hallmann, Christine and Hemp, Andreas and H{\"o}lzel, Norbert and Jung, Kirsten and Klaus, Valentin H. and Klein, Alexandra M. and Kleinebecker, Till and Lange, Markus and M{\"u}ller, J{\"o}rg and Nacke, Heiko and Prati, Daniel and Renner, Swen C. and Rothenw{\"o}hrer, Christoph and Schall, Peter and Schulze, Ernst-Detlef and Socher, Stephanie A. and Tscharntke, Teja and T{\"u}rke, Manfred and Weiner, Christiane N. and Weisser, Wolfgang W. and Westphal, Catrin and Wolters, Volkmar and Wubet, Tesfaye and Fischer, Markus}, title = {Extensive und j{\"a}hrlich wechselnde Nutzungsintensit{\"a}t f{\"o}rdert den Artenreichtum im Gr{\"u}nland}, series = {ANLIEGEN NATUR}, volume = {38}, journal = {ANLIEGEN NATUR}, number = {1}, issn = {1864-0729}, pages = {86 -- 95}, language = {de} } @misc{GlaweKleinSchmidt, author = {Glawe, Christoph and Klein, Marten and Schmidt, Heiko}, title = {ODT augmented RaNS}, series = {Book of Abstracts of the 93rd Annual Meeting of the International Association of Applied Mathematics and Mechanics}, journal = {Book of Abstracts of the 93rd Annual Meeting of the International Association of Applied Mathematics and Mechanics}, publisher = {GAMM e.V.}, address = {Dresden}, pages = {368}, language = {en} } @misc{GlaweKleinSchmidt, author = {Glawe, Christoph and Klein, Marten and Schmidt, Heiko}, title = {Stochastic deconvolution of wall statistics in Reynolds-averaged Navier-Stokes simulations based on one-dimensional turbulence}, series = {Proceedings in applied mathematics and mechanics : PAMM}, volume = {23}, journal = {Proceedings in applied mathematics and mechanics : PAMM}, number = {3}, issn = {1617-7061}, doi = {10.1002/pamm.202300055}, pages = {9}, abstract = {Reynolds-averaged Navier-Stokes simulation (RaNS) is state-of-the-art for numerical analysis of complex flows at high Reynolds number. Standalone RaNS may yield a reasonable estimate of the wall-shear stress and turbulent drag if a proper wall-function is prescribed, but detailed turbulence statistics cannot be obtained, especially at the wall. This lack in modeling is addressed here by a stochastic deconvolution strategy based on a stochastic one-dimensional turbulence (ODT) model. Here, a one-way coupling strategy is proposed in which a forcing term is computed from the balanced RaNS solution that is in turn utilized in the ODT model. The temporally developing ODT solution exhibits turbulent perturbations but relaxes toward the local RaNS solution due to resolved molecular-diffusive processes. It is demonstrated that the approach is able to recover the distribution of positive wall-shear stress fluctuations in turbulent channel flow. When formulated as post-processing tool, it is suggested that RaNS can be enhanced by ODT providing economical means for local high-fidelity numerical modeling based on a low-fidelity flow solution.}, language = {en} } @misc{KleinMedinaMendezSchoepsetal., author = {Klein, Marten and Medina M{\´e}ndez, Juan Al{\´i} and Sch{\"o}ps, Mark Simon and Schmidt, Heiko and Glawe, Christoph}, title = {Towards physics-based nowcasting of the instantaneous wind velocity profile using a stochastic modeling approach}, series = {STAB Jahresbericht 2024 zum 24. DGLR-Fachsymposium der STAB, 13. - 14. November 2024, Regensburg}, journal = {STAB Jahresbericht 2024 zum 24. DGLR-Fachsymposium der STAB, 13. - 14. November 2024, Regensburg}, publisher = {Deutsche Str{\"o}mungsmechanische Arbeitsgemeinschaft, STAB}, address = {Regensburg [et al.]}, pages = {162 -- 163}, abstract = {The primary objective of this contribution is to provide an overview of the regime-spanning forward modeling capabilities offered by the stochastic one-dimensional turbulence model. The focus is on the applicability of the model and its validation for neutral and stable atmospheric boundary layer flows as a prerequisite for future applications to challenging atmospheric conditions.}, language = {en} } @incollection{KleinGlaweEhlertetal., author = {Klein, Marten and Glawe, Christoph and Ehlert, Mark Simon and Medina M{\´e}ndez, Juan Al{\´i} and Schmidt, Heiko}, title = {Stochastic modeling of intermittent inflow turbulence in the atmospheric boundary layer}, series = {New Results in Numerical and Experimental Fluid Mechanics XV : contributions to the 24th STAB/DGLR Symposium, Regensburg, Germany, 2024}, booktitle = {New Results in Numerical and Experimental Fluid Mechanics XV : contributions to the 24th STAB/DGLR Symposium, Regensburg, Germany, 2024}, editor = {Dillmann, Andreas and Heller, Gerd and Kr{\"a}mer, Ewald and Breitsamer, Christian and Wagner, Claus and Krenkel, Lars}, publisher = {Springer Nature Switzerland}, address = {Cham}, isbn = {978-3-032-11115-9}, issn = {1612-2909}, doi = {10.1007/978-3-032-11115-9_63}, pages = {684 -- 693}, abstract = {Wind turbine predesign is challenged by the representation of site-specific wind conditions. A good deal of that challenge lies in the modeling of the inflow turbulence in the atmospheric boundary layer (ABL). A stochastic one-dimensional turbulence (ODT) model is applied to an idealized neutrally stratified ABL and evolves the instantaneous velocity profile with full-scale resolution. The model is able to reproduce the law of the wall consistently after an initial calibration with the surface drag law. Investigating turbulent time series of the horizontal velocity components it is demonstrated that the model generates physically justified intermittency features with increasing turbulence intensity.}, language = {en} }