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- Ashok, A. (author), Ragni, D. (author), Van Oudheusden, B.W. (author), Scarano, F. (author) conference paper 2008
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- Ashok, A. (author), Ragni, D. (author), Van Oudheusden, B.W. (author), Scarano, F. (author) conference paper 2008
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- Caridi, Giuseppe Carlo Alp (author), Ragni, D. (author), Sciacchitano, A. (author), Scarano, F. (author) conference paper 2015
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- Sinnige, T. (author), Lynch, K.P. (author), Ragni, D. (author), Eitelberg, G. (author), Veldhuis, L.L.M. (author) conference paper 2015
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- Sinnige, T. (author), van Kuijk, JJ (author), Lynch, K.P. (author), Ragni, D. (author), Eitelberg, G. (author), Veldhuis, L.L.M. (author) conference paper 2015
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Sinnige, T. (author), Malgoezar, A.M.N. (author), Ragni, D. (author), Snellen, M. (author), Eitelberg, G. (author), Veldhuis, L.L.M. (author)An experimental investigation was performed at the Large Low-speed Facility of the German-Dutch wind tunnels (DNW-LLF) to study the pylon interactions associated with pusher propellers. The aerodynamic and aeroacoustic effects of pylon trailing edge blowing and swirl recovery vanes (SRVs) were evaluated. The pylon installation increased the...conference paper 2015
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Azijli, I. (author), Sciacchitano, A. (author), Ragni, D. (author), Palha da Silva Clerigo, A. (author), Dwight, R.P. (author)The present work proposes a methodology for the a posteriori quantification of the uncertainty of pressure data retrieved from PIV measurements. It relies upon the Bayesian framework, where the posterior distribution (probability distribution of the true velocity, given the PIV measurements) is obtained from the prior distribution (prior...conference paper 2015
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Baldacchino, D. (author), Ragni, D. (author), Simao Ferreira, C.J. (author), Van Bussel, G.J.W. (author)In this work, the measured modulated integral boundary layer (IBL) characteristics of low-profile vortex generators (VGs) are used to validate new developments in a viscousinviscid interaction code which is modified to incorporate the effect of the passive mixing devices. The motivations are laid out and sample validation data is presented...conference paper 2015
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Avallone, F. (author), Ragni, D. (author), Schrijer, F.F.J. (author), Scarano, F. (author), Cardone, G. (author)In this study, the mean flow organization in the symmetry plane of the recirculation region ahead of a cylindrical roughness element immersed in an incoming laminar boundary layer at Mach number equal to 6.5 is investigated. The flow topology is inspected with planar particle image velocimetry (PIV), InfraRed (IR) Thermography and Schlieren flow...conference paper 2015
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Lignarolo, L. (author), Ragni, D. (author), Simao Ferreira, C.J. (author), van Bussel, G.J.W. (author)The present paper is the summary of 3 years of research on the wake aerodynamics of horizontal axis wind turbine at Delft University of Technology, the Netherlands. In particular, the main results and the conclusions of two experimental campaigns are collected. The underlying research question is: how do the near-wake turbulent flow structures...conference paper 2015
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Sinnige, T. (author), Ragni, D. (author), Eitelberg, G. (author), Veldhuis, L.L.M. (author)Pylon-mounted pusher propellers suffer from installation effects due to the interaction between the pylon and the propeller. The impact of angular inflow on these installation effects was quantified at the Large Low-Speed Facility of the German-Dutch wind tunnels (DNW-LLF). Particle-image-velocimetry measurements showed that the pylon wake's...conference paper 2016
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Sinnige, T. (author), Ragni, D. (author), Eitelberg, G. (author), Veldhuis, L.L.M. (author)The aerodynamic interaction e_ects characteristic of pusher propellers were studied at the Large Low-Speed Facility of the German{Dutch wind tunnels (DNW-LLF). A propeller model was positioned downstream of a pylon equipped with a trailing-edge blowing system. Surface-pressure transducers integrated into the propeller blades con_rmed the local...conference paper 2016
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- Li, Q. (author), Öztürk, K. (author), Ragni, D. (author), Sinnige, T. (author), Eitelberg, G. (author), Veldhuis, L.L.M. (author), Yangang, Wang (author) conference paper 2017
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Arce Leon, C.A. (author), Merino Martinez, R. (author), Ragni, D. (author), Pröbsting, S. (author), Avallone, F. (author), Singh, A. (author), Madsen, Jesper (author)Trailing edge serrations have been proven to work as a passive noise reduction device. Nevertheless, they have also previously been found to increase noise in a particular frequency range, argued in earlier research to be due to the misalignment of the serrations with the direction of the flow in the wake. It emerges as a high-frequency noise...conference paper 2017
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Merino Martinez, R. (author), van der Velden, W.C.P. (author), Avallone, F. (author), Ragni, D. (author)Trailing-edge serrations are passive noise reduction add-ons widely used in wind-turbine applications. This study presents acoustic beamforming results of microphone array measurements of a cambered airfoil (DU96-W-180) in a closed-section wind-tunnel at a Reynolds number of industrial interest. Two different serration geometries with different...conference paper 2017
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Gamme, S. (author), De Oliveira Andrade, G.L. (author), Ragni, D. (author), Lau, F. (author)A fast, linear scaling vortex method is presented to study inviscid incompressible flow problems involving one or more actuator disks. Building upon previous efforts that were limited to axi-symmetric flow cases, the proposed methodology is able to handle arbitrary configurations with no symmetry constraints. Applications include the conceptual...conference paper 2017
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de Vries, R. (author), Sinnige, T. (author), della Corte, B. (author), Avallone, F. (author), Ragni, D. (author), Eitelberg, G. (author), Veldhuis, L.L.M. (author)<br/>conference paper 2017
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della Corte, B. (author), Sinnige, T. (author), de Vries, R. (author), Avallone, F. (author), Ragni, D. (author), Eitelberg, G. (author), Veldhuis, L.L.M. (author)<br/>conference paper 2017
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van der Velden, W.C.P. (author), Avallone, F. (author), Ragni, D. (author)The relation between the far-field noise and the flow field, in presence of serrated and combed-serrated trailing edge, is studied to explain the associated noise reduction mechanisms. Both serration geometries are retrofitted to a NACA 0018 wing. Computations are carried out by solving the fully explicit, transient, compressible Lattice...conference paper 2017
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- Avallone, F. (author), van der Velden, W.C.P. (author), Merino Martinez, R. (author), Ragni, D. (author) conference paper 2017