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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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Boatto, U. (author), Bonnet, Jean-Paul (author), Avallone, F. (author), Ragni, D. (author)The design of efficient rotor blades is affected by the accuracy of aerodynamic prediction methods for load distributions and power computations. Research showed that the accuracy of BEMT-based industrial codes decreases at high inflow-speed under uniform aligned steady conditions. The identified reasons are inaccuracies in the semi-empirical...conference paper 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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Fuerkaiti, Y. (author), Casalino, D. (author), Avallone, F. (author), Ragni, D. (author)This paper presents a noise propagation approach based on the Gaussian beam tracing (GBT) method that accounts for multiple reflections over three-dimensional terrain topology and atmospheric refraction due to horizontal and vertical variability in wind velocity. A semi-empirical formulation is derived to reduce truncation error in the beam...journal article 2023
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Zhang, Y. (author), Avallone, F. (author), Watson, S.J. (author)In recent years, with the development of the wind power industry and the increase in the number of wind turbines, the condition monitoring of blades and the detection of damage are increasingly important. In this work, a new non-contact damage-detection approach is experimentally investigated based on the measurement of airfoil aerodynamic noise...journal article 2022
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VanDercreek, Colin (author), Avallone, F. (author), Ragni, D. (author), Snellen, M. (author)Cavities placed along wind tunnel walls can attenuate the turbulent boundary layer (TBL) fluctuations as they propagate into the cavity. Placing microphones within the cavities can thus improve the signal-to-noise ratio of acoustic data. However, standing waves form within these cavities distorting the acoustic measurements. This work uses a...journal article 2022
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Fiscaletti, D. (author), Luesutthiviboon, S. (author), Avallone, F. (author), Casalino, D. (author)Streamwise fences for the reduction of the trailing-edge noise are experimentally investigated on a NACA633018 airfoil. Interchangeable trailing-edge inserts with streamwise fences of different spacing and height are tested in an anechoic wind tunnel. Far-field trailing-edge noise was measured by an array of microphone and the airfoil drag was...conference paper 2022
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Rego, Leandro (author), Avallone, F. (author), Ragni, D. (author), Casalino, D. (author)This paper investigates the mechanisms by which flow-permeable materials provide noise reduction in an installed jet configuration. Numerical simulations are carried out with a flat plate placed in the near field of a single-stream subsonic jet (M<sub>a</sub>=0.3 and M<sub>a</sub>=0.5). The trailing-edge region of the plate is replaced by...journal article 2022
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Teruna, C. (author), Rego, Leandro (author), Casalino, D. (author), Ragni, D. (author), Avallone, F. (author)This manuscript presents the application of a recently developed noise reduction technology, constituted by poro-serrated stator blades on a full-scale aircraft model, in order to reduce rotor-stator interaction noise in the fan stage. This study was carried out using the commercial lattice Boltzmann solver 3DS-SIMULIA PowerFLOW. The simulation...journal article 2022
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Grande, E. (author), Romani, G. (author), Ragni, D. (author), Avallone, F. (author), Casalino, D. (author)This paper presents an experimental investigation of a propeller operating at low Reynolds numbers and provides insights into the role of aerodynamic flow features on both propeller performances and noise generation. A propeller operating at a tip Reynolds number regime of 4.3 × 10<sup>4</sup> − 4.38 × 10<sup>4</sup> is tested in an anechoic...journal article 2022
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Zhang, Y. (author), Avallone, F. (author), Watson, S.J. (author)In this work, aimed at the development of an aeroacoustics-based wind turbine blade damage detection approach, the noise scattered from two airfoils with damage at the trailing edge or at the leading edge is investigated. Four trailing edge cracks (with width of 0.2, 0.5, 1.0 and 2.0 mm) and four leading edge erosion configurations (consisting...journal article 2022
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Rego, Leandro (author), Avallone, F. (author), Ragni, D. (author), Casalino, D. (author), Denayer, Hervé (author)A Helmholtz resonator with a curved cavity is studied for reducing jet-installation noise in a configuration comprised by a subsonic jet and a nearby flat plate. The face-sheet and cavity are designed with the Guess method and the impedance is verified through an experiment and a simulation of an impedance tube. Both single and double degree...journal article 2022
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Fuerkaiti, Y. (author), Casalino, D. (author), Avallone, F. (author), Ragni, D. (author)This work presents a novel noise propagation approach based on the Gaussian Beam Tracing (GBT) method that accounts for complex source directivity, weather conditions, and irregular ground topology for the evaluation of the noise footprint. The approach takes a precomputed noise sphere as input and propagates the acoustic pressure...conference paper 2022
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Teruna, C. (author), Rego, Leandro (author), Casalino, D. (author), Ragni, D. (author), Avallone, F. (author)High-fidelity numerical simulations have been performed to investigate the noise reduction capability of porous leading-edge treatments for mitigating rotor-stator interaction noise in a full-scale aircraft model. The aircraft model consists of the NASA High-Lift Common Research Model (HL-CRM) airframe combined with an up-scaled Source...conference paper 2022
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Meirelles Pereira, L. (author), Bonomo, Lucas A. (author), da Silva, Andrey R. (author), Cordioli, Júlio A. (author), Avallone, F. (author)Scaled-resolved numerical simulations using the lattice-Boltzmann Very Large Eddy Simulation method are performed to compute the acoustic impedance of a realistic multi-cavity single degree of freedom liner grazed by a turbulent boundary layer. Numerical results are assessed against experimental impedance measurements carried out in grazing flow...conference paper 2022
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Gondrum, M. (author), Niemöller, A. (author), Meinke, M. (author), Schröder, W. (author), Rubio Carpio, A. (author), Ragni, D. (author), Avallone, F. (author)The time resolved flow and acoustic fields around a simplified two-wheel nose landing gear configuration featuring brakes, torque link, and a detachable fairing are investigated by numerical and experimental means. The flow field is computed by a lattice Boltzmann method with a collision step based on countable cumulants. Numerical near field...conference paper 2022
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Grande, E. (author), Ragni, D. (author), Avallone, F. (author), Casalino, D. (author)This paper explains the presence and relevance of noise caused by a laminar separation bubble (LSB) on a propeller operating at low-Reynolds number. Microphone measurements of a propeller with both clean and forced boundary layer transition blades are carried out in an anechoic wind tunnel by varying the propeller advance ratio J from 0 to 0...conference paper 2022
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Rego, Leandro (author), Zamponi, R. (author), Ragni, D. (author), Avallone, F. (author), Casalino, D. (author), Cruellas Bordes, M. (author)An experimental investigation on jet-installation noise reduction with permeable flaps on an aircraft half-model is performed, focusing on the effects on the noise levels as well as on the aerodynamic properties of the model (lift and drag forces). A nozzle with an exit diameter = 113 mm is included for generating a single-stream jet flow in...conference paper 2022
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Zamponi, R. (author), Avallone, F. (author), Ragni, D. (author), van der Zwaag, S. (author)Coating a circular cylinder with porous materials constitutes an effective passive strategy for reducing the flow-induced noise linked to the vortex shedding. Despite the number of investigations in the last decade, the noise-mitigation mechanisms associated with this technique remain unclear. The present research aims to clarify the role played...conference paper 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