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Laguarda, L. (author), Hickel, S. (author), Schrijer, F.F.J. (author), van Oudheusden, B.W. (author)Wall-resolved large-eddy simulations (LES) are performed to investigate Reynolds number effects in supersonic turbulent boundary layers (TBLs) at Mach 2.0. The resulting database covers more than a decade of friction Reynolds number Re<sub>τ</sub>, from 242 to 5554, which considerably extends the parameter range of current high-fidelity...journal article 2024
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Savazzi, A.C.M. (author), Nuijens, Louise (author), De Rooy, Wim (author), Janssens, M. (author), Siebesma, A.P. (author)This study investigates momentum transport in shallow cumulus clouds as simulated with the Dutch Atmospheric Large Eddy Simulation (DALES) for a 150 3 150 km2 domain east of Barbados during 9 days of EUREC4A. DALES is initialized and forced with the mesoscale weather model HARMONIE-AROME and subjectively reproduces observed cloud patterns....journal article 2024
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Manchester, Emily Louise (author), Pirola, S. (author), Pirola, Sergio (author), Mastroiacovo, Giorgio (author), Polvani, Gianluca (author), Pontone, Gianluca (author), Xu, Xiao Yun (author)Aortic valve disease is often treated with bioprosthetic valves. An alternative treatment is aortic valve neocuspidization which is a relatively new reparative procedure whereby the three aortic cusps are replaced with patient pericardium or bovine tissues. Recent research indicates that aortic blood flow is disturbed, and turbulence effects...journal article 2024
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Li, X. (author)This thesis contributes to the effective and efficient application of unsteady adjoint methods to Adaptive Mesh Refinement (AMR) for Large Eddy Simulation (LES). Three aspects, i.e., subgrid-scale model error, storage cost of high-dimensional data, and stability of the adjoint problem for turbulent flows, were studied to make adjoint-based mesh...doctoral thesis 2023
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Jansson, F.R. (author), Janssens, M. (author), Grönqvist, Johanna H. (author), Siebesma, A.P. (author), Glassmeier, F. (author), Attema, Jisk (author), Azizi, Victor (author), Satoh, Masaki (author), Sato, Yousuke (author)Small shallow cumulus clouds (less-than 1 km) over the tropical oceans appear to possess the ability to self-organize into mesoscale (10–100 km) patterns. To better understand the processes leading to such self-organized convection, we present Cloud Botany, an ensemble of 103 large-eddy simulations on domains of 150 km, produced by the Dutch...journal article 2023
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Zamponi, R. (author), Satcunanathan, S. (author), Moreau, S. (author), Meinke, M. (author), Schröder, W. (author), Schram, C. (author)Integrating a porous material into the structure of an aerofoil constitutes a promising passive strategy for mitigating the noise from turbulence–body interactions that has been extensively explored in the past few decades. When a compact permeable body is considered in the aeroacoustic analogy derived by Curle to predict this noise source, a...journal article 2023
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Allaerts, D.J.N. (author), Quon, Eliot (author), Churchfield, Matt (author)Reproducing realistic date- and site-specific unsteady wind conditions in large-eddy simulations is becoming increasingly useful in wind energy. How to run a large-eddy simulation to match observed conditions, however, remains an open research question. One approach that has received considerable attention is mesoscale-to-microscale coupling,...journal article 2023
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Bao, Hesheng (author), Han, Jinlin (author), Zhang, Yan (author), Di Matteo, Andrea (author), Roekaerts, D.J.E.M. (author), Van Oijen, Jeroen (author), Somers, Bart (author)In the current work, the Flamelet Generated Manifold (FGM) method is applied with large-eddy simulation (LES) to investigate the effect of methane on dual-fuel (DF) spray ignition. The diesel surrogate n-dodecane is injected as the so-called pilot fuel into selected lean methane–air mixtures, ranging from ϕ<sub>CH<sub>4</sub></sub>=0 to ϕ<sub...journal article 2023
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van Campenhout, O.W.G. (author), van Nesselrooij, M. (author), Lin, Y. (author), Casacuberta Puig, J. (author), van Oudheusden, B.W. (author), Hickel, S. (author)Although several previous studies have reported a potential drag-reducing effect of dimpled surfaces in turbulent boundary layers, there is a lack of replicability across experiments performed by different research groups. To contribute to the dialogue, we scrutinize one of the most studied dimple geometries reported in the literature, which...journal article 2023
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Jansson, F.R. (author)HPCI User Report for the project Organization of shallow cumulus clouds on the Fugaku supercomputer.report 2022
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Chen, Linfeng (author), Hulshoff, S.J. (author), Dong, Yuhong (author)The underlying physical mechanism of the residual-based large eddy simulation (LES) based on the variational multiscale (VMS) method is clarified. Resolved large-scale energy transportation equation is mathematically derived for turbulent kinetic energy budget analysis. Firstly, statistical results of benchmark turbulent channel flow at Re...journal article 2022
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Cascioli, E. (author), Keijers, S. (author), Van Tichelen, K. (author), Vesper, J.E. (author), Kenjeres, S. (author)In the present work, we have applied a combined dynamic large-eddy simulation (LES) and direct numerical simulation (DNS) approach for a three-dimensional planar jet in a turbulent forced convection regime (Re = 18000) with a heated co-flow. Results from LES are compared with Reynolds Averaged Navier-Stokes (RANS) simulations and experimental...journal article 2022
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Hu, F. (author), Helfer, K.C. (author), Siebesma, A.P. (author), Hanssen, R.F. (author)Atmospheric delay has a profound impact on synthetic aperture radar (SAR) interferometry, inducing a spatial signal that significantly devaluates interferometric products. While the wide-scale variability of the atmosphere can be adequately modeled with global or regional weather models, it is especially the turbulent and convective part of the...journal article 2022
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Helfer, K.C. (author)Cumulus clouds ('fair-weather clouds') form as a result of atmospheric convection and have vertical extents between a few hundred metres (humilis species) and several kilometres (congestus species). They are a major source of uncertainty in the estimation of climate sensitivity by climate models. In order to reach more agreement in cloud changes...doctoral thesis 2021
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Alhaddad, S.M.S. (author)Underwater slope failure is a common problem in the fields of geotechnical, dredging and hydraulic engineering, posing a major risk to submerged infrastructure and flood defences along coasts, rivers, and lakes. The term ‘flow slide’ refers to a specific, complex failure mechanism of underwater slopes, which occurs when a substantial amount of...doctoral thesis 2021
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Helfer, K.C. (author), Nuijens, Louise (author), Vijay Dixit, V. (author)Motivated by the abundance of low clouds in the subtropics, where the easterly trade winds prevail, we study the role of shallow convection in the momentum budget of the trades. To this end, we use ICON-LEM hindcasts run over the North Atlantic for 12 days corresponding to the NARVAL1 (winter) and NARVAL2 (summer) flight campaigns. The...journal article 2021
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Helfer, K.C. (author), Nuijens, Louise (author)A growing body of literature investigates convective organization, but few studies to date have sought to investigate how wind shear plays a role in the spatial organization of shallow (trade-wind) convection. The present study hence investigates the morphology of precipitating marine cumulus convection using large-eddy-simulation experiments...journal article 2021
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Li, X. (author), Hulshoff, S.J. (author), Hickel, S. (author)Adaptive mesh refinement (AMR) is potentially an effective way to automatically generate computational meshes for high-fidelity simulations such as Large Eddy Simulation (LES). Adjoint methods, which are able to localize error contributions, can be used to optimize the mesh for computing a physical quantity of interest (e.g. lift, drag)...journal article 2021
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Vijay Dixit, V. (author), Nuijens, Louise (author), Helfer, K.C. (author)It is well known that subtropical shallow convection transports heat and water vapor upwards from the surface. It is less clear if it also transports horizontal momentum upwards to significantly affect the trade winds in which it is embedded. We utilize unique multiday large-eddy simulations run over the tropical Atlantic with ICON-LEM to...journal article 2021
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Jansson, F.R. (author), Edeling, Wouter (author), Attema, Jisk (author), Crommelin, Daan (author)In this study, we investigate uncertainties in a large eddy simulation of the atmosphere, employing modern uncertainty quantification methods that have hardly been used yet in this context. When analysing the uncertainty of model results, one can distinguish between uncertainty related to physical parameters whose values are not exactly known...journal article 2021