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LeBlanc, B.P. (author)Society is finally entering a new age of renewable energy development. For the first time it is truly conceivable to power a vast majority of global energy use with a combination of wind, solar, and other forms of low carbon, renewable power. The rise of electrification and so called ”Power to X”, where renewable energy is used to create other...doctoral thesis 2024
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Mertens, C. (author)This thesis presents a novel measurement approach for aeroelastic wind tunnel testing. The key novelty of this approach is the integrated measurement of aerodynamic and structural quantities using an optical technique. The considered approach consists of combined measurements of flow tracer particles and structural markers using a Lagrangian...doctoral thesis 2023
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D'Aguanno, A. (author)The flight envelope of an aircraft operating at high subsonic velocities is bounded by several limitations, one of these consists in thewing experiencing oscillations of a shockwave on its suction side for a certain range ofMach number (Ma), angle of attack (®) and Reynolds number (Re). This phenomenon is referred to as transonic buffet and it...doctoral thesis 2023
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Gutiérrez, R. (author), Zamponi, R. (author), Ragni, D. (author), Llorente, Elena (author), Aranguren, Patricia (author)Modern wind turbines employ thick airfoils in the outer region of the blade with strong adverse pressure gradients and high sensitivity to flow separation, which can be anticipated by leading-edge roughness. However, Reynolds average Navier-Stokes simulations currently overpredict the Reynolds shear stresses near the surface, and the flow...journal article 2023
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Meloni, S. (author), de Paola, E. (author), Grande, E. (author), Ragni, D. (author), Stoica, L. G. (author), Di Marco, A. (author), Camussi, R. (author)Propeller noise generally exhibits a rich mixture of tonal and broadband components related to different physical mechanisms. Specifically, the tones are characterized by having deterministic and persistent characteristics, while the broadband counterpart has random behaviour. The separation is essential for the experimenters as they provide...journal article 2023
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Spoelstra, A.M.C.M.G. (author)The research presented in this thesis introduces a new measurement concept for on-site aerodynamic measurements based on large-scale stereoscopic particle image velocimetry (stereo-PIV) measurements past an athlete, a vehicle or an object travelling through a quiescent environment. The analysis of the momentumdeficit past the transit poses the...doctoral thesis 2022
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van Meerkerk, M. (author), Poelma, C. (author), Hofland, Bas (author), Westerweel, J. (author)We present an experimental study on the gas flow field development over a plunging breaking wave prior to impact on a vertical wall. The variability of wave impact pressure over repeated measurements is well known (Bagnold, 1939). The formation of instabilities on the wave crest are postulated to be the main source of impact pressure variability...journal article 2022
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D'Aguanno, A. (author), Schrijer, F.F.J. (author), van Oudheusden, B.W. (author)This experimental study investigates the possibility of controlling transonic buffet by means of a trailing edge flap with an upward deflection (referred to as “upper trailing edge flap”, or: UTEF). Different geometries (straight and serrated) and dimensions of UTEFs (with heights ranging between 1 and 2% of the chord) have been studied with...journal article 2022
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Guo, Y. (author), Jia, W. (author), Markine, V.L. (author), Jing, Guoqing (author)Ballast rheology is a phenomenon that describes movements of ballast particles due to the discrete nature, which eventually leads to the ballast bed fluid deformation after a long-time service. In most cases, ballast rheology is the main reason of track irregularity that leads to some track defects, e.g., hanging sleeper and mud spots....journal article 2021
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Melani, P. F. (author), Balduzzi, F. (author), Brandetti, L. (author), Ferreira, Carlos (author), Bianchini, A. (author)Simulation methods ensuring a level of fidelity higher than that of the ubiquitous Blade Element Momentum theory are increasingly applied to VAWTs, ranging from Lifting-Line methods, to Actuator Line or Computational Fluid Dynamics (CFD). The inherent complexity of these machines, characterised by a continuous variation of the angle of attack...journal article 2020
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Rietveld, M.W.J. (author), de Rijke, D. (author), Langeveld, J.G. (author), Clemens, F.H.L.R. (author)Urban runoff (re)mobilises solids present on the street surface and transport them to urban drainage systems. The solids reduce the hydraulic capacity of the drainage system due to sedimentation and on the quality of receiving water bodies due to discharges via outfalls and combined sewer overflows (CSOs) of solids and associated pollutants....journal article 2020
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Thota Radhakrishnan, A.K. (author), Poelma, C. (author), van Lier, J.B. (author), Clemens, F.H.L.R. (author)Transition from laminar to turbulent flow of non-Newtonian fluids is investigated using velocimetry data. These data are obtained by applying particle image velocimetry to images obtained through ultrasound imaging (echography). This yielded the observation of intermittent structures (puffs and slugs) that are formed during transition. Post...journal article 2020
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Scharnowski, S. (author), Sciacchitano, A. (author), Kahler, Christian J. (author)For the reliable estimation of velocity vector fields by means of particle image velocimetry (PIV), the cross-correlation functions calculated from the signal within each interrogation window must feature a distinct peak that represents the average shift of the particle image ensemble. A high valid detection probability (VDP) of the correct...journal article 2019
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Guo, Y. (author), Markine, V.L. (author), Zhang, X. (author), Qiang, Weile (author), Jing, Guoquig (author)The performance and deformation of ballast bed are significantly influenced by the particle morphology (size and shape), the rheology (translation and rotation), and the degradation (breakage and abrasion). Regarding the ballast particle morphology, the ballast particle size is generally measured by sieving and described with the Particle Size...review 2019
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Adam, Florian (author), Terra, W. (author), Sciacchitano, A. (author)Large-scale particle image velocimetry (PIV) is used to characterize the dynamics of the unsteady wake of a non-pedalling full-scale cyclist. This to provide better understanding of the flow structures that generate the aerodynamic drag. Instantaneous flow fields are acquired and averaged to obtain the time-average flow topology. Afterwards,...journal article 2019
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Haidari, A.H. (author), Heijman, Sebastiaan (author), Uijttewaal, W.S.J. (author), van der Meer, W.G.J. (author)Feed spacer orientation affects the velocity pattern and pressure drop of spacer-filled channels such as those encountered in Spiral-wound Membrane (SWM) modules of Reverse Osmosis (RO). However, there are only limited numbers of experimental studies on this topic. This study sets out to reveal more detailed information on the pressure drop...journal article 2019
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Timoshevskiy, Mikhail V. (author), Pervunin, Konstantin S. (author), Markovich, Dmitriy M. (author), Hanjalic, K. (author)We studied cavitating flow over the suction side of a symmetric 2D foil - a scaled-down model of high-pressure hydroturbine guide vanes (GV) - in different cavitation regimes at several attack angles. High-speed imaging was used to analyze spatial patterns and time dynamics of the gas-vapor cavities, as well as for evaluating the...conference paper 2019
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van Tilborg, Frank (author), van Raemdonck, G.M.R. (author), Sciacchitano, A. (author), Casalino, D. (author)This article analyses the flow field between two 1/8-scale Generalized European Transport System (GETS) models which are placed in a two-vehicle platoon at close distances. Numerical simulations using the lattice Boltzmann method together with a wind tunnel experiment (open jet facility, OJF) were executed. Next to balance measurements,...journal article 2019
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Haidari, A.H. (author), Heijman, Sebastiaan (author), van der Meer, W.G.J. (author)Making improvements to feed spacers of spiral-wound membrane (SWM) modules of reverse osmosis (RO) is a necessary step towards a wider application of these modules. This study sets out to evaluate the performance of six commercial feed spacers by comparing their actual velocity profiles and their pressure drop. Velocity profiles are obtained...journal article 2018
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Schneiders, J.F.G. (author), Scarano, F. (author), Jux, C. (author), Sciacchitano, A. (author)This study describes the working principles of the coaxial volumetric velocimeter (CVV) for wind tunnel measurements. The measurement system is derived from the concept of tomographic PIV in combination with recent developments of Lagrangian particle tracking. The main characteristic of the CVV is its small tomographic aperture and the...journal article 2018