- document
- Ashok, A. (author), Ragni, D. (author), Van Oudheusden, B.W. (author), Scarano, F. (author) conference paper 2008
- document
- Ashok, A. (author), Ragni, D. (author), Van Oudheusden, B.W. (author), Scarano, F. (author) conference paper 2008
- document
-
Ragni, D. (author), Ashok, A. (author), van Oudheusden, B.W. (author), Scarano, F. (author)The present investigation assesses a procedure to extract the aerodynamic loads and pressure distribution on an airfoil in the transonic flow regime from particle image velocimetry (PIV) measurements. The wind tunnel model is a two-dimensional NACA-0012 airfoil, and the PIV velocity data are used to evaluate pressure fields, whereas lift and...journal article 2009
- document
-
Ragni, D. (author), Van Oudheusden, B.W. (author), Scarano, F. (author)The flow field at the tip region of a scaled DHC Beaver aircraft propeller, running at transonic speed, has been investigated by means of a multi-plane stereoscopic particle image velocimetry setup. Velocity fields, phase-locked with the blade rotational motion, are acquired across several planes perpendicular to the blade axis and merged to...journal article 2011
- document
-
Lorenzoni, V. (author), Ragni, D. (author)An experimental study of the flow inside a saxophone mouthpiece in playing conditions is carried out by means of particle image velocimetry at high acquisition rate. Planar velocity measurements on the midsection of a Plexiglas tenor saxophone mouthpiece are performed, respectively, in the mouthpiece baffle and in the reed channel. Sequences of...journal article 2012
- document
-
Ragni, D. (author)The thesis describes the application of particle image velocimetry (PIV) to study the aerodynamic loads of airfoils and aircraft propellers. The experimental work focuses on the development of a measurement procedure to infer the pressure of the flow field from the velocity distribution obtained by PIV velocimetry. The technique offers important...doctoral thesis 2012
- document
- Caridi, Giuseppe Carlo Alp (author), Ragni, D. (author), Sciacchitano, A. (author), Scarano, F. (author) conference paper 2015
- document
- Sinnige, T. (author), Lynch, K.P. (author), Ragni, D. (author), Eitelberg, G. (author), Veldhuis, L.L.M. (author) conference paper 2015
- document
- 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
- document
-
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
- document
-
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
- document
-
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
- document
-
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
- document
-
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
- document
-
Avallone, F. (author), Pröbsting, S. (author), Ragni, D. (author)The three-dimensional flow field over the suction side of a NACA 0018 airfoil with trailing-edge serrations was studied by means of time-resolved tomographic particle image velocimetry. Mean flow results show that the boundary layer thickness decreases along the streamwise direction with a corresponding reduction of the size of the turbulent...journal article 2016
- document
-
De Oliveira Andrade, G.L. (author), Balbino dos Santos Pereira, R. (author), Timmer, W.A. (author), Ragni, D. (author), Lau, F. (author), van Bussel, G.J.W. (author)There are many ways to learn from data. Our first experiment consisted in reproducing the way aerodynamicists work [2] with a genetic optimizer. The data pool was too narrow and asymptotic tendencies were unreliable. Our 2nd Experiment, a simple version of [4], had a virtually unlimited data pool and used neural networks. Results were better,...poster 2016
- document
-
Baldacchino, D. (author), Ferreira, Carlos (author), Ragni, D. (author), van Bussel, G.J.W. (author)In this work, we present a simple inviscid point vortex model to study the dynamics of asymmetric vortex rows, as might appear behind misaligned vortex generator vanes. Starting from the existing solution of the in_nite vortex cascade, a numerical model of four base-vortices is chosen to represent two primary counter-rotating vortex pairs and...journal article 2016
- document
-
Arce Leon, C.A. (author), Merino Martinez, R. (author), Ragni, D. (author), Avallone, F. (author), Snellen, M. (author)Trailing edge serrations designed to reduce airfoil self-noise are retrofitted on a NACA 0018 airfoil. An investigation of the boundary layer flow statistical properties is performed using time-resolved stereoscopic PIV. Three streamwise locations over the edge of the serrations are compared. An analysis of the results indicates that, while...journal article 2016
- document
-
De Oliveira Andrade, G.L. (author), Balbino dos Santos Pereira, R. (author), Ragni, D. (author), Avallone, F. (author), van Bussel, G.J.W. (author)The article seeks to unify the treatment of conservative force interactions between axi-symmetric bodies and actuators in inviscid ow. Applications include the study of hub interference, di_user augmented wind turbines and boundary layer ingestion propeller con_gurations. The conservation equations are integrated over in_nitesimal streamtubes to...journal article 2016
- document
-
Arce Leon, C.A. (author), Ragni, D. (author), Pröbsting, S. (author), Scarano, F. (author), Madsen, Jesper (author)The flow past a NACA 0018 airfoil with sawtooth trailing edge serrations has been investigated using stereoscopic particle image velocimetry (PIV). The serration flap angle and airfoil incidence are varied in order to study the effect of secondary flow establishing between the suction and pressure sides of the serrations. The flow topology...journal article 2016