Searched for: subject%3A%22Aeroacoustic%22
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Gehlen, Tjeu (author)
With the ever-increasing issues caused by global warming, the emission of carbon dioxide has to be minimized. With the transport section being responsible for 24% of global emissions, the demand for electric alternatives is on the rise. <br/>The electrification of passenger vehicles comes with benefits like a smoother driving experience,...
master thesis 2024
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Hinssen, Yara (author)
Aeroacoustic testing in wind tunnels is crucial for understanding and mitigating the noise generation mechanisms in several devices while maintaining satisfactory aerodynamic performance in the conceptual design stage. However, current measurements in closed-section wind tunnels face challenges in terms of installation, due to the effect of the...
master thesis 2024
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Brandetti, L. (author)
In urban areas, vertical-axis wind turbines (VAWTs) show promise due to their omnidirectional design, addressing challenges faced by traditional horizontal-axis turbines (HAWTs). Despite significant progress in urban VAWTs, extensive multidisciplinary research is needed to optimise their efficiency and use in such environments. <br/><br/>This...
doctoral thesis 2024
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Xu, Ying (author), Casalino, D. (author), Zhang, Xiao Zheng (author), Zhang, Yong Bin (author), Bi, Chuan Xing (author)
A time-domain inverse aeroacoustic method based on the convective Ffowcs Williams–Hawkings equation is presented. The method allows to determine, in real-time, the unsteady forces exerted on rotating blades in the presence of a moving medium. The inversion procedure is based on a space-time regularization with a mixed l1,2-norm, which guarantees...
journal article 2024
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Zamponi, R. (author), Avallone, F. (author), Ragni, D. (author), Schram, C. (author), van der Zwaag, S. (author)
This paper elucidates the link between the near-wake development of a circular cylinder coated with a porous material in a low Mach-number flow and the related aerodynamic sound attenuation. It accomplishes this by formulating the cylinder flow-induced noise as a diffraction problem. The necessity for such an approach is driven by...
journal article 2024
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Barker, Evan (author)
As market growth projections for Urban Air Mobility vehicles (UAMs) skyrocket, their presence in urban environments is likely to become increasingly prevalent, as will their noise. This creates a disturbance to both humans and wildlife, previously unaffected by aircraft noise. Further reinforcing the concern is the new multi-rotor designs, which...
master thesis 2023
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Lima Pereira, L.T. (author)
Wind-turbine noise can restrict the growing implementation of renewable energy sources and their application close to urban environments. The largest contributor to the noise of modern turbines is the scattering of the turbulent fluctuations at the blade trailing edge. This source of noise is directly correlated with the turbine’s extracted...
doctoral thesis 2023
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Yunus, F. (author)
doctoral thesis 2023
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Bouman, Naomi (author)
Airborne wind energy systems offer a promising approach for renewable energy generation. However, the noise emissions associated with these systems should be understood and minimized as well to promote their integration and (social) acceptance. This research aims to identify the noise sources of airborne wind energy systems, systems with leading...
master thesis 2023
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Zhang, Y. (author), Avallone, F. (author), Watson, S.J. (author)
In this paper, the feasibility of using far-field acoustic measurements as a non-contact monitoring technique for wind turbine blade leading edge erosion is assessed. For this purpose, a DU96 W180 airfoil with several eroded leading edge configurations of different severities is experimentally investigated. The eroded leading edges are designed...
journal article 2023
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Trotta, Luca (author)
High-frequency combustion instabilities represent the main technical risk faced by design engineers when developing new chemical rocket propulsion systems. Such instabilities are driven by the coupling between the flames’ heat release rate and the combustion chamber’s acoustic field. As such, they can only be assessed during detailed design...
master thesis 2023
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Avallone, F. (author), Ragni, D. (author)
Noise reduction is one of the major challenges to the societal acceptance of wind turbines. Aerodynamic noise sources are the dominant ones, assuming that mechanical noise can be reduced by correct insulation and periodic maintenance of the gearbox and drive train and by adding insulating material in the wind-turbine nacelle. The dominant...
book chapter 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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VanDercreek, Colin (author)
<br/>Aerodynamic noise produced by aircraft, wind turbines, and other objects subjected to airflow contribute to environmental noise pollution, which adversely affects human and animal health. Consequently, governments impose restrictions on aircraft and wind turbine noise levels. These restrictions can have an economic impact by limiting...
doctoral thesis 2022
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Rego, Leandro (author)
Aircraft noise levels have been significantly reducedwith the introduction of high-bypass ratio turbofan engines, particularly jet noise due to turbulence mixing. This, however, has led to engines with larger diameters and a closer coupling between them and the airframe. As a result, interactions between the exhaust jet flow and the wing give...
doctoral thesis 2022
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Vergés i Plaza, Guillem (author)
Trailing-edge noise can be the dominant noise source of diverse industrial applications, including wind turbines. Noise regulations may limit the power production and installation of new wind farms. There is a need to reduce it. In order to achieve so, we first need to predict it, and to do so we need experimental data to support and validate...
master thesis 2022
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de Gruijl, Wouter (author)
To make propellers more viable as a greener alternative to jet engines, the issue of propeller noise needs to be addressed. Previous propeller design optimization studies rarely take into account the effects on aerodynamic and aeroacoustic performance due to non-uniform inflow, the type of flow the propeller would experience if it was installed...
master thesis 2022
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Teruna, C. (author)
Public annoyances due to noise emission in aviation and wind energy sectors are expected to become more severe in the near future with increasing number of civilian flights and wind turbine installations. Such trend demands for deeper investigations into the noise generation mechanisms and the means to mitigate them. This dissertation addresses...
doctoral thesis 2022
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Koutsoukos, Alexandros (author)
The Advisory Council of Aviation Research has set the future goals of sustainable development in aviation by reducing pollutant emissions of CO2 by 75% and 90% in NOx emissions per passenger kilometre and noise emission by 65% of the perceived noise level compared with the measurements in 2000. This demand has led to the development of new...
master thesis 2022
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Romani, G. (author), Grande, E. (author), Avallone, F. (author), Ragni, D. (author), Casalino, D. (author)
This paper presents a computational study of flow incidence effects on the aeroacoustics of a propeller operating at low blade-tip Mach numbers. The numerical flow solution is obtained by using the Lattice-Boltzmann/Very Large Eddy Simulation method, while far-field noise is computed through the Ffowcs-Williams &amp; Hawkings' acoustic...
journal article 2022
Searched for: subject%3A%22Aeroacoustic%22
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