A5027430836- Aerodynamics and Acoustics in Jet Flows
- Fluid Dynamics and Turbulent Flows
- Wind and Air Flow Studies
- Combustion and flame dynamics
- Acoustic Wave Phenomena Research
- Computational Fluid Dynamics and Aerodynamics
- Aerodynamics and Fluid Dynamics Research
- Image and Signal Denoising Methods
- Heat Transfer Mechanisms
- Vehicle Noise and Vibration Control
- Cavitation Phenomena in Pumps
- Fluid Dynamics and Vibration Analysis
- Particle Dynamics in Fluid Flows
- Meteorological Phenomena and Simulations
- Wind Energy Research and Development
- Plasma and Flow Control in Aerodynamics
- Ship Hydrodynamics and Maneuverability
- Hydraulic and Pneumatic Systems
- Plant Water Relations and Carbon Dynamics
- Flow Measurement and Analysis
- Advanced Aircraft Design and Technologies
- Fluid Dynamics and Heat Transfer
- Cyclone Separators and Fluid Dynamics
- Rocket and propulsion systems research
- Turbomachinery Performance and Optimization
Roma Tre University
2016-2025
European University of Rome
2008-2013
Istituto Nazionale per Studi ed Esperienze di Architettura Navale
2008
Laboratoire de Mécanique des Fluides et d'Acoustique
2008
Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre
1998-2000
École Normale Supérieure de Lyon
1996-1997
Sapienza University of Rome
1995-1996
Centre National de la Recherche Scientifique
1996
In the present study mechanisms of evolution propeller tip and hub vortices in transitional region far field are investigated experimentally. The experiments involved detailed time-resolved visualizations velocimetry measurements were aimed at examining effect spiral-to-spiral distance on wake instability transition. this regard, three propellers having same blade geometry but different number blades considered. outlined dependence and, particular, a streamwise displacement transition...
Numerical experiments are conducted to study high-Rayleigh-number convective turbulence ($Ra$ ranging from $2\times 10^6$ up 10^{11}$) in a $\Gamma=1/2$ aspect-ratio cylindrical cell heated below and cooled above filled with gaseous helium ($Pr=0.7$). The numerical approach allows three-dimensional velocity, vorticity temperature fields be analysed. Furthermore, several probes placed within the fluid volume, permitting point-wise velocity time series extracted. Taking advantage of data...
A summary of experimental results on structure functions obtained using extended self-similarity in various flow configurations (jet, grid, mixing layer, duct flow, cylinder) at Reynolds numbers ranging between 30 and 5000 is presented.
Abstract An experimental study of the pressure field generated by a subsonic, single stream, round jet is presented. The investigation conducted in near-field region at subsonic Mach numbers (up to 0.9) and Reynolds $\mathit{Re}\gt 1{0}^{5} $ . main task present work analysis acoustic characterization its spectral properties. To this aim, novel post-processing technique based on application wavelet transforms method accomplishes separation nearly Gaussian background fluctuations, interpreted...
The effect of Prandtl number on the dynamics a convective turbulent flow is studied by numerical experiments. In particular, three series experiments have been performed; in two them Rayleigh spanned about decades while was set equal to 0.022 (mercury) and 0.7 (air). third series, contrast, we fixed at 6×10 5 varied from 0.0022 up 15. results shown that, depending number, there are distinct regimes; first ( Pr [lsim ]0.35) dominated large-scale recirculation cell that most important ‘engine’...
Experimental data obtained in various turbulent flows are analysed by means of orthogonal wavelet transforms. Several configurations analysed: homogeneous grid turbulence at low and very Re λ , fully developed jet moderate high . It is shown the decomposition combination with form scaling named extended self-similarity that some statistical properties may be to low- flows. Indeed, universal related intermittency observed down ≃10. Furthermore, use a new conditional averaging technique...
This work describes an experimental study of the flow field and wall pressure fluctuations induced by quasi-two-dimensional incompressible turbulent boundary layers overflowing a forward-facing step (FFS). Pressure are measured upstream downstream instrumented FFS model installed inside large scale recirculation water tunnel, while two-dimensional (2D) velocity fields close to via 2D particle image velocimetry (PIV). The overall physics is studied in terms averaged vorticity for different...
An experimental investigation of pressure fluctuations generated by a single-stream compressible jet is carried out in an anechoic wind tunnel. Measurements are performed using linear array microphones installed the near region and polar arc far field. The main focus paper on analysis Three novel signal processing techniques presented to provide decomposition near-field into hydrodynamic acoustic components. procedures all based application wavelet transform measured data possess distinctive...
Abstract 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 persistent characteristics, while counterpart has random behaviour. The separation is essential for experimenters as they provide information on sources. In this framework, study presents novel wavelet-based method able separate emitted low Reynolds number propeller into its components....
Flow visualizations and phase-averaged particle image velocimetry (PIV) measurements of a jet in crossflow configuration at very low Reynolds numbers ( Re j ≃ 100) are performed water tunnel for jet-to-cross-stream velocity ratios R ranging from 1.5 to 4.5. The PIV vector fields flow visualizations, carried out by injecting methylene blue dye the laser induced fluorescence (LIF) technique, analysed characterize effect on formation evolution large-scale vortices. It is shown that two distinct...
In this paper, noise emissions from two pusher propellers installed on a wing are investigated both experimentally and numerically. Aerodynamic aeroacoustic measurements were carried out in the acoustically treated open test section of Pininfarina Wind Tunnel encompassed extensive parametric analyses terms geometrical configurations flight conditions. Significant reduction is achieved by installing propeller at wingtip (up to 3 dB), as well increasing its distance 2 dB). The experimental...
Wavelet transform has become a common tool for processing non-stationary signals in many different fields. The present paper reports review of some applications wavelet aeroacoustics with special emphasis on the analysis experimental data taken compressible jets. focus is three classes wavelet-based signal procedures: (i) conditional statistics; (ii) acoustic and hydrodynamic pressure separation; (iii) stochastic modeling. approaches are applied to an database consisting time series measured...
The statistical properties of the streamwise velocity fluctuations in a fully developed turbulent channel flow are studied experimentally by means single hot wire measurements. intermittency features, through scaling moments structure function computed using extended self- similarity and probability density wavelet coefficients, found to be dependent on distance from wall. maximum effects observed region between buffer layer inner part logarithmic where it is known that bursting phenomenon,...
The transitions from the onset of convection to fully developed turbulence a Rayleigh–Bénard flow, in low-aspect-ratio cell and mercury, are studied through three-dimensional numerical simulation Navier–Stokes equations. calculation growth rate azimuthal energy modes permitted accurate determination critical Rayleigh number for establishment convective regime (Rac=3750) which is good agreement with analytical other results. Increasing number, flow remained steady up Ra≃2.11×104 when an...
A wavelet-based conditional analysis of unsteady flow and sound signals highlights the role intermittent perturbations both in generation field an aerofoil tip leakage experiment. It is shown how most probable generated at pressure side edge are convected through gap swept downstream along suction past trailing corner, where they radiate sound. The nascent sources identified localized clearance between 40% 60% chord. also found that time dependence averaged structures scales with inverse...
Abstract A numerical database (Bernardini & Pirozzoli, Phys. Fluids , vol. 23, 2011, 085102) is analysed to investigate cross-statistics of wall-pressure fluctuations induced by supersonic turbulent boundary layers developing over a rigid smooth wall without pressure gradient. The Mach number spans from 2 4 and relatively large range Reynolds numbers considered. It shown, for the first time, that at such high very similar usually observed in incompressible flow conditions. Furthermore,...
In this work an experimental investigation of the near-field pressure a compressible jet is presented. The proper orthogonal decomposition (POD) fluctuations measured by linear array microphones performed in order to provide streamwise evolution structure. wavenumber–frequency spectrum space–time fields re-constructed using each POD mode computed physical interpretation terms hydrodynamic/acoustic nature. Specifically, non-radiating hydrodynamic, radiating acoustic and ‘hybrid’...
Combined near and far field aeroacoustic measurements have been carried out during an original laboratory scale low Mach number (0–0.3) experiment about the tip leakage flow past a single non-rotating airfoil. Such were made possible by use of airfoil located in potential core open jet anechoic wind tunnel Ecole Centrale de Lyon. The was mounted between two flat plates. A strong clearance achieved without rotation paying special attention to choice which 5% camber, 10% thickness NACA5510...