Searched for: author%3A%22Lima+Pereira%2C+L.T.%22
(1 - 12 of 12)
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Fiscaletti, D. (author), Lima Pereira, L.T. (author), Ragni, D. (author)
The present study focuses on the application of finlet rails as a passive technique of flow control to mitigate trailing-edge noise. Finlet rails are small cylinders whose axes are aligned along the streamwise direction, transversally positioned with respect to the trailing edge. In the first part of this study, the effects of finlet geometry...
journal article 2024
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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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Luesutthiviboon, S. (author), Lima Pereira, L.T. (author), Ragni, D. (author), Avallone, F. (author), Snellen, M. (author)
Experimental results on trailing-edge (TE) noise from a NACA 63<sub>3</sub> –018 airfoil are presented for a chord-based Reynolds number Re<sub>c</sub> range between 2 × 10<sup>5</sup> and 3 × 10<sup>6</sup>. Far-field TE noise from the baseline airfoil with a straight TE and TE serrations is measured with varying Re<sub>c</sub>, angle of...
journal article 2023
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Lima Pereira, L.T. (author), Avallone, F. (author), Ragni, D. (author), Scarano, F. (author)
This work discusses the physics of noise reduction achieved from serrated trailing–edges and its impact by the serration design. An experimental campaign is carried out with a benchmark 2D model based on a NACA 63<sub>3</sub>–018 airfoil. Different trailing-edge serrations are tested under several flow speeds and angles of attack conditions...
journal article 2023
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Lima Pereira, L.T. (author), Avallone, F. (author), Ragni, D. (author), Buck, Steven (author), Oerlemans, S. (author)
This work proposes a semi-empirical framework to predict the noise of wind turbines with serrated trailing edge blades. The framework is employed for studying the reduction of the noise of the SWT 2.3-93 benchmark wind turbine. The framework is verified against field acoustic measurements of the real wind-turbine model and of noise reduction...
conference paper 2023
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Lima Pereira, L.T. (author), Avallone, F. (author), Ragni, D. (author), Scarano, F. (author)
A physical description of the flow mechanisms that govern the distribution of the wall-pressure fluctuations over the surface of a serrated trailing edge is proposed. Three main mechanisms that define the variation of turbulent pressure fluctuations across the serrated edge are discussed and semi-empirical models are formulated accordingly....
journal article 2022
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Vergés i Plaza, G. (author), Fischer, Andreas (author), Lylloff, Oliver (author), Bak, Christian (author), Olsen, Anders S. (author), Luesutthiviboon, S. (author), Lima Pereira, L.T. (author), Ragni, D. (author), Avallone, F. (author)
An experimental aero-acoustic characterisation of the NACA 63 <sub>3</sub>-018 airfoil is presented in this study, featuring trailing-edge noise emissions with and without serrations. Measurements have been carried out for a chord-based Reynolds number range between 0.18 × 10 <sup>6</sup> and 4.8 × 10 <sup>6</sup> . Two airfoil models with...
conference paper 2022
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Lima Pereira, L.T. (author), Ragni, D. (author), Avallone, F. (author), Scarano, F. (author)
The impact of aerodynamic loading on a serrated trailing edge is studied experimentally. Aerodynamic and acoustic measurements are conducted on a sawtooth-shaped trailing edge, retrofitted to a flat plate featuring a trailing-edge flap, and placed at incidence to the free-stream flow. The turbulent flow across the trailing edge is inspected...
journal article 2022
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Lima Pereira, L.T. (author), Avallone, F. (author), Ragni, D. (author)
iew Video Presentation: https://doi-org.tudelft.idm.oclc.org/10.2514/6.2021-2179.vid<br/><br/>The unsteady surface pressure fluctuations over trailing-edge serrations retrofitted to the benchmark NACA 633-018 profile are experimentally measured. Miniaturized unsteady pressure transducers installed on the serration surface are used to describe...
conference paper 2021
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Lima Pereira, L.T. (author), Merino Martinez, R. (author), Ragni, D. (author), Gómez-Ariza, David (author), Snellen, M. (author)
This paper explores the advantages of combining asynchronous microphone array measurements for acoustic source mapping in two and three–dimensional applications. Four different approaches are considered, three consisting of the combination of the source maps (arithmetic mean, geometric mean, and minimum value), and a fourth one obtained by...
journal article 2021
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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
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Lima Pereira, L.T. (author), Ragni, D. (author), Avallone, F. (author), Scarano, F. (author)
Abstract: Measurements of distributed surface pressure fluctuations over trailing-edge serrations at a Reynolds number Re <sub>θ</sub> = 4900 are performed with time-resolved 3D particle imaging velocimetry using helium filled soap bubbles as flow tracers. The sparse velocity vector field obtained with Lagrangian particle tracking is densely...
journal article 2020
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