- document
-
Merino Martinez, R. (author), Kennedy, John (author), Bennett, Gareth J. (author)The landing gear system is the dominant airframe noise source for most modern commercial aircraft during approach. This manuscript reports the results from the ALLEGRA (Advanced Low Noise Landing (Main and Nose) Gear for Regional Aircraft) project. This project assessed the performance of several highly realistic low–noise technologies (LNTs)...journal article 2021
- document
-
Merino Martinez, R. (author), Rubio Carpio, A. (author), Lima Pereira, L.T. (author), van Herk, S.W.L. (author), Avallone, F. (author), Ragni, D. (author), Kotsonis, M. (author)The newly refurbished vertical tunnel (V-tunnel) at Delft University of Technology has been redesigned as a state-of-the-art facility for research in aeroacoustics (A-tunnel), as well as fundamental studies in laminar-turbulent transition and flow control. This manuscript focuses on the design and refurbishment aspects of the facility,...journal article 2020
- document
-
Khurana, Siddhant (author)Over the past decades, numerous methods have been used to study acoustic liners through their impedance, of which numerical methods are of particular interest. Despite their advantages, numerical methods are bounded by certain drawbacks. One such drawback stems from the need to accurately discretize the liner geometry, which can lead to large...master thesis 2020
- document
-
Avallone, F. (author), Ragni, D. (author), Casalino, D. (author)Lattice-Boltzmann Very-Large-Eddy Simulations of two Diffuser-Augmented Wind Turbines are carried out to investigate the effect of the tip-clearance (TC) ratio on both the flow field and the far-field noise. The DonQi® wind turbine, a three blades ducted rotor with nominal TC of 2.5%, is chosen as reference test case. The second configuration...journal article 2020
- document
-
Dighe, V.V. (author), Avallone, F. (author), van Bussel, G.J.W. (author)Ducted Wind Turbines (DWTs) can be used for energy harvesting in urban areas where non-uniform inflows might be the cause of aerodynamic and acoustic performance degradation. For this reason, an aerodynamic and aeroacoustic analysis of DWTs in yawed inflow condition is performed for two duct geometries: a baseline commercial DWT model, DonQi®...journal article 2020
- document
-
Dighe, V.V. (author)Ducted Wind Turbines (DWTs) are one of the many concepts that have been proposed to improve the energy extraction from wind in comparison to bare wind turbines. In reviewing the DWT studies, investigations based on the combined use of theoretical, computational, and experimental techniques have been presented. Although indicated in these studies...doctoral thesis 2020
- document
-
Merino Martinez, R. (author), Luesutthiviboon, S. (author), Zamponi, R. (author), Rubio Carpio, A. (author), Ragni, D. (author), Sijtsma, P. (author), Snellen, M. (author), Schram, Christophe (author)In this paper, the performance of four acoustic imaging methods: conventional frequency domain beamforming (CFDBF), functional beamforming (FUNBF), enhanced high resolution CLEAN–SC (EHR–CLEAN–SC) and generalized inverse beamforming (GIBF), is investigated in terms of accuracy and variability. Three experimental test cases are considered: 1)...journal article 2020
- document
-
Shubham, Shubham (author)Noise is a major issue in Urban Air Mobility vehicles, especially due to its operation in the urban environment. One of the major sources of noise is the rotor, and thus, there is a need to optimize the rotor design for aerodynamics and aeroacoustics. A possible technological solution is represented by Co-rotating rotors (i.e., two rotors...master thesis 2020
- document
-
Teruna, C. (author), Manegar, F.A. (author), Avallone, F. (author), Ragni, D. (author), Casalino, D. (author), Carolus, T. (author)Open-cell porous materials have been reported as a promising concept for mitigating turbulent boundary-layer trailing-edge noise. This manuscript examines the aeroacoustics of a porous trailing edge to study its noise reduction mechanisms. Numerical investigations have been carried out for a NACA 0018 aerofoil with three different types of...journal article 2020
- document
-
Rego, L. (author), Avallone, F. (author), Ragni, D. (author), Casalino, D. (author)The link between jet-installation noise and the near-field flow features of the corresponding isolated jet is studied by means of lattice-Boltzmann numerical simulations. The computational set-up consists of a flat plate placed in proximity to a jet, replicating the interaction benchmark study carried out at NASA Glenn. Installation effects...journal article 2020
- document
-
Romani, G. (author), Ye, Q. (author), Avallone, F. (author), Ragni, D. (author), Casalino, D. (author)Aim of this paper is to investigate the effects of the turbulent flow developing over a fuselage on fan noise for BLI embedded propulsion systems. Such configurations can suffer from inlet flow distortions and ingestion of turbulence at the fan plane with consequent impact on both broadband and tonal fan noise. The analysis is performed on a...journal article 2020
- document
-
Malgoezar, A.M.N. (author)Humans localize sound incessantly using the ears and it proves to be important of<br/>our awareness. It can also be a cause of annoyance to the community whenever<br/>sound is in the form of noise. Due to increase of wealth, industry, technology and<br/>corresponding globalization there is a large increase of noise. Especially with the<br/...doctoral thesis 2019
- document
-
Tamaro, Simone (author)The addition of porous material to the trailing edge of airfoils was studied numerically and experimentally. The purpose of this work is to inspect whether the penalization method can be successfully used to describe flows through porous media. In the numerical study, the penalization method was applied to the incompressible Navier-Stokes...master thesis 2019
- document
-
Haddaoui, Mohammed (author)Turboprop engines are known for their high fuel efficiency on short-range missions compared to turbofan engines. A disadvantage of turboprop engines is the noise they produce. The dominant noise source of the turboprop engine is the propeller. The goal of this research is to develop a propeller source noise model which has the future goal to...master thesis 2019
- document
-
Merino Martinez, R. (author), Sijtsma, P. (author), Snellen, M. (author), Finez, A. (author), Herold, G. (author), Malgoezar, A.M.N. (author), Pereira, A. (author), Sarradj, E. (author), Simons, D.G. (author)Phased microphone arrays have become a well-established tool for performing aeroacoustic measurements in wind tunnels (both open-jet and closed-section), flying aircraft, and engine test beds. This paper provides a review of the most well-known and state-of-the-art acoustic imaging methods and recommendations on when to use them. Several...journal article 2019
- document
-
Mayer, Jonathan (author)For many aerospace applications, the dominant airfoil self-noise source is Turbulent Boundary Layer Trailing Edge (TBL-TE) noise. The replacement of solid airfoil trailing edges with permeable materials proved to be an adequate noise reduction mean in previous studies. This thesis project contributes to the development of innovative permeable...master thesis 2019
- document
-
Romani, G. (author), Casalino, D. (author)The aim of this paper is to assess the accuracy, capabilities and computational performances of the Lattice-Boltzmann/Very Large Eddy Simulation Method to predict the unsteady aerodynamic loads, the rotor wake development and the noise radiation of helicopter rotors in strong Blade-Vortex Interaction conditions. The numerical flow solution is...journal article 2019
- document
-
Merino Martinez, R. (author)With the continuous growth in demand for air traffic and wind turbines, the noise emissions they generate are becoming an increasingly important issue. To reduce their noise levels, it is essential to obtain accurate information about all the sound sources present. Phased microphone arrays and acoustic imaging methods allow for the estimation of...doctoral thesis 2018
- document
-
Kurelek, J.W. (author), Kotsonis, M. (author), Yarusevych, S. (author)Transition and flow development in a separation bubble formed on an airfoil are studied experimentally. The effects of tonal and broadband acoustic excitation are considered since such acoustic emissions commonly result from airfoil self-noise and can influence flow development via a feedback loop. This interdependence is decoupled, and the...journal article 2018
- document
-
Brandetti, Livia (author)The increase of energy consumption as well as the need to reduce green-house emissions trigger the shift from a fossil-fuel based society towards a sustainable society. With a constant increase in the installed power capacity, wind plays a key role in the global energy framework. The improvement of the technology opens up new targets for the...master thesis 2018