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Xue, S. (author), Schrijer, F.F.J. (author), van Oudheusden, B.W. (author), Wang, Chengpeng (author), Shi, Zhiwei (author), Cheng, Keming (author)In this paper the configurations of shock wave-boundary layer interactions (SWBLI) are studied theoretically and experimentally in Mach number 2 and 2.5 flows on test models with various wedge angles ranging from to. The proposed theoretical method couples the free interaction theory (FIT) with the minimum entropy production (MEP) principle...journal article 2020
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Seitz, Arne (author), Luisa Habermann, Anaïs (author), van Sluis, M. (author)The paper discusses optimality constellations for the design of boundary layer ingesting propulsive fuselage concept aircraft under special consideration of different fuselage fan power train options. Therefore, a rigorous methodical approach for the evaluation of the power saving potentials of propulsive fuselage concept aircraft...journal article 2020
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van Hooft, J.A. (author)The scalar front generated by the horizontal self advection of a dipolar vortex through a mod-est scalar gradient is investigated. This physical scenario is an idealization of the emergenceof strong temperature ramps in the stable atmospheric boundary layer. The proposed mecha-nism is discussed and a two-dimensional analogy is studied in depth...journal article 2020
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Couvreux, Fleur (author), Bazile, Eric (author), Rodier, Quentin (author), Maronga, Björn (author), Matheou, Georgios (author), Chinita, Maria J. (author), Edwards, John (author), van Stratum, Bart J.H. (author), van Heerwaarden, Chiel C. (author), Huang, Jing (author), Moene, Arnold F. (author), Cheng, Anning (author), Fuka, Vladimir (author), Basu, S. (author), Bou-Zeid, Elie (author), Canut, Guylaine (author), Vignon, Etienne (author)In polar regions, where the boundary layer is often stably stratified, atmospheric models produce large biases depending on the boundary-layer parametrizations and the parametrization of the exchange of energy at the surface. This model intercomparison focuses on the very stable stratification encountered over the Antarctic Plateau in 2009. Here...journal article 2020
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Mertens, C. (author), Wolf, C. Christian (author), Gardner, Anthony D. (author), Schrijer, F.F.J. (author), van Oudheusden, B.W. (author)Advanced data processing methods for detecting unsteady boundary layer transition in periodic aerodynamic processes by means of infrared thermography measurements are presented. The thermal radiation emitted from the heated suction surface of a pitching airfoil model in subsonic flow is measured with an infrared camera. The unsteady boundary...journal article 2020
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Romani, G. (author), Ye, Q. (author), Avallone, F. (author), Ragni, D. (author), Casalino, D. (author)Aim of this paper is to investigate the effects of the turbulent flow developing over a fuselage on fan noise for BLI embedded propulsion systems. Such configurations can suffer from inlet flow distortions and ingestion of turbulence at the fan plane with consequent impact on both broadband and tonal fan noise. The analysis is performed on a...journal article 2020
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Pini, M. (author), de Servi, C.M. (author)This paper documents a numerical study on entropy generation in zero-pressure gradient, laminar boundary layers of adiabatic non-ideal compressible fluid flows. The entropy generation is expressed in terms of dissipation coefficient $$C:\mathrm {d}$$ and its dependency on free-stream Mach number, fluid molecular complexity, and flow non...conference paper 2020
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Bosveld, Fred C. (author), Baas, P. (author), Beljaars, Anton C.M. (author), Holtslag, Albert A.M. (author), de Arellano, Jordi Vilà Guerau (author), van de Wiel, B.J.H. (author)An overview is given of 50-year Cabauw observations and research on the structure and dynamics of the atmospheric boundary layer. It is shown that over time this research site with its 200-m meteorological tower has grown into an atmospheric observatory with a comprehensive observational program encompassing almost all aspects of the...journal article 2020
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Izett, J.G. (author), van de Wiel, B.J.H. (author)The overall depth of a fog layer is one of the important factors in determining the hazard that a fog event presents. With discrete observations and often coarse numerical grids, however, fog depth cannot always be accurately determined. To address this, we derive a simple analytical relation that describes the change in depth of a fog...journal article 2020
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Basu, S. (author), He, Ping (author), DeMarco, Adam W. (author)We use a database of direct numerical simulations to evaluate parametrizations for energy dissipation rate in stably stratified flows. We show that shear-based formulations are more appropriate for stable boundary layers than commonly used buoyancy-based formulations. As part of the derivations, we explore several length scales of turbulence...journal article 2020
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Basu, S. (author), DeMarco, Adam W. (author), He, Ping (author)In this study, we explore several integral and outer length scales of turbulence which can be formulated by using the dissipation of temperature fluctuations (χ) and other relevant variables. Our analyses directly lead to simple yet non-trivial parameterizations for both spatially-averaged χ¯ and the structure parameter of temperature (CT2)....journal article 2020
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Dai, Y. (author), Basu, S. (author), Maronga, Björn (author), de Roode, S.R. (author)We have identified certain fundamental limitations of a mixing-length parametrization used in a popular turbulent kinetic energy-based subgrid-scale model. Replacing this parametrization with a more physically realistic one significantly improves the overall quality of the large-eddy simulation (LES) of stable boundary layers. For the range...journal article 2020
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Henriquez, M. (author)This thesis is about the hydrodynamic processes that occur when a nearshore sandbar migrates towards the shore driven by the waves. These processes are relevant because process-based morphological models have difficulty simulating coastal accretion events in contrast to erosion events. Simulating accretion events is important for engineering...doctoral thesis 2019
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CUI, Guangyao (author), PAN, C. (author), WU, Di (author), Ye, Q. (author), WANG, Jinjun (author)The characteristics of turbulent boundary layer over streamwise aligned drag reducing riblet surface under zero-pressure gradient are investigated using particle image velocimetry. The formation and distribution of large-scale coherent structures and their effect on momentum partition are analyzed using two-point correlation and probability...journal article 2019
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Baldacchino, D. (author)Vortex generators have become a ubiquitous sight on the modern wind turbine blade. These small, passive devices can increase the energy extraction potential of a rotor, but their subtle footprint disguises the technical difficulties associated with designing and integrating them onto wind turbine blades. The complexity of rotor inflow and the...doctoral thesis 2019
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Björnsson, Olafur (author)Flame flashback is an intrinsic problem in lean premixed combustion. Due to higher flame speeds and lower quenching distances, hydrogen-rich fuel mixtures are especially prone to boundary layer flashback (BLF). Research at TU Munich (Eichler 2011, Baumgartner 2014) has resulted in new insights into the mechanism of BLF, revealing a strong...master thesis 2019
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Janssens, Martin (author)Today's leading projections of climate change predicate on Atmospheric General Circulation Models (GCMs). Since the atmosphere consists of a staggering range of scales that impact global trends, but computational constraints prevent many of these scales from being directly represented in numerical simulations, GCMs require "parameterisations'' -...master thesis 2019
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Mayer, Jonathan (author), Rubio Carpio, A. (author), Ragni, D. (author)The present work analyses broadband noise scattering from permeable trailing edges with identical micro-structure but under a change of temperature. Experiments are performed in an anechoic wind tunnel using a NACA0018 airfoil at chord-based Reynolds numbers between 1.88 × 10<sup>5</sup> and 3.14 × 10<sup>5</sup> and no incidence. A...journal article 2019
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de Groot, Geiske (author)The non-linear relation between Evapotranspiration (ET) and the atmospheric moisture demand in terms of vapor pressure deficit (VPD) has been widely reported. Observations point towards a diverse range of potential drivers; however, without uncovering why the identified factors are found to control diurnal ET-VPD hysteresis. Modelling efforts...master thesis 2019
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Baskaran, Pradeep (author)Aircraft fuel efficiency, noise, and emissions are some of the most important aspects being addressed in the research of novel aircraft configurations for meeting the future requirements of the aviation industry. One concept which has the potential for improving the aircraft fuel efficiency is called the boundary layer ingestion (BLI)....master thesis 2019