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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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Peng, K. (author), Avallone, F. (author), Kotsonis, M. (author)Plasma-based flow control poses a simple and robust technique for transition delay on swept wings. However, a clear understanding of how plasma actuators affect crossflow instabilities is necessary to develop and mature crossflow control based on plasma actuators. In this paper, the design of a new swept wing model optimised for the study of...conference paper 2021
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Teruna, C. (author), Avallone, F. (author), Ragni, D. (author), Casalino, D. (author), Rubio Carpio, A. (author)This manuscript presents a numerical investigation of an open-cell 3D-printed perme-able/porous insert used to reduce turbulent boundary layer-trailing edge (TBL-TE) noise. The matrix topology of the insert resembles the lattice of diamond atoms, and thus, it is also referred to as the diamond trailing edge (TE). The porous insert replaces...conference paper 2021
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Schroeder, Lucas (author), Spillere, André M. N. (author), Bonomo, Lucas A. (author), da Silva, Andrey R. (author), Cordioli, Júlio A. (author), Avallone, F. (author)View Video Presentation: https://doi-org.tudelft.idm.oclc.org/10.2514/6.2021-2144.vid<br/><br/>The physics behind acoustic liners attenuation in the presence of flow and high sound pressure level is still a matter of debate. Similarly, discrepancies between experimental results and numerical data have been linked to the boundary conditions used...conference paper 2021
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Arcondoulis, Elias J. G. (author), Liu, Yu (author), Yang, Yannian (author), Ragni, D. (author), Rubio Carpio, A. (author), Avallone, F. (author)View Video Presentation: https://doi-org.tudelft.idm.oclc.org/10.2514/6.2021-2226.vid<br/><br/>The mechanisms responsible for vortex shedding reduction, due to the application of a porous coating to a smooth cylinder placed in uniform flow, are still uncertain despite several numerical and experimental studies. To help understand these...conference paper 2021
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Avallone, F. (author), Casalino, D. (author)View Video Presentation: https://doi-org.tudelft.idm.oclc.org/10.2514/6.2021-2169.vid<br/><br/>High-fidelity lattice-Boltzmann very-large-eddy simulations have been carried out to investigate the behaviour of a single-cavity multi-orifice acoustic liner grazed by a turbulent boundary layer at free-stream Mach number equal to 0.3 and an acoustic...conference paper 2021
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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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Goyal, J. (author), Sinnige, T. (author), Avallone, F. (author), Ferreira, Carlos (author)Regenerative propellers offer many potential benefits such as improved maneuverability, reduced landing run, and decreased community noise, besides the potential to reduce energy consumption by recovering energy during descent and landing. Since the blade loading in regenerative mode will be opposite to that in the conventional propulsive mode,...conference paper 2021
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Dighe, V.V. (author), Suri, Dhruv (author), Avallone, F. (author), van Bussel, G.J.W. (author)Ducted Wind Turbines (DWTs) are used for energy harvesting in urban areas where the flow is non-uniform in comparison to the free-field because of the presence of buildings or other surface discontinuities. For this reason, the aerodynamic performance and far-field noise of DWTs in yawed inflow conditions must be characterized. Both the...conference paper 2020
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Avallone, F. (author), Manjunath, P. (author), Ragni, D. (author), Casalino, D. (author)A lattice-Boltzmann Very Large Eddy simulation of a multi-orifice acoustic liner, grazed by a turbulent flow at Mach number equal to 0:3 and a planar acoustic wave with amplitude equal to 130 dB and frequency equal to 1800 Hz, is carried out. The geometry of the liner replicates the experiments carried out in the Grazing Flow Impedance Tube ...conference paper 2019
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Ye, Q. (author), Avallone, F. (author), Ragni, D. (author), Choudhari, Meelan (author), Casalino, D. (author)The effects of a finite, spanwise-periodic array of cylindrical roughness elements on boundary layer transition over a NACA 0012 airfoil are investigated at a chord-based Reynolds number of 1.44×10<sup>5</sup> by using hotwire anemometry and infrared thermography. Both the number and the spanwise spacing of roughness elements in the array are...conference paper 2019
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Rego, Leandro (author), Avallone, F. (author), Ragni, D. (author), Casalino, D. (author)A numerical investigation on jet-installation noise is performed using a software based on the Lattice-Boltzmann Method. A flat plate is placed in the irrotational hydrodynamic field of the jet, i.e. outside of the plume, resulting in noise increase due to the scattering of instability waves at the plate trailing edge. The configuration adopted...conference paper 2019
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Avallone, F. (author), Casalino, D. (author), Ragni, D. (author)A computational study of two Diffuser-Augmented Wind Turbines (DAWTs) is carried out to investigate both the hydrodynamic flow field and the far-field noise. The two configurations differ for the tip-clearance ratio, defined as the ratio between the tip clearance and the rotor radius. The DonQi® wind turbine, a three blades ducted rotor, is...conference paper 2019
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de Vries, R. (author), van Arnhem, N. (author), Avallone, F. (author), Ragni, D. (author), Vos, Roelof (author), Eitelberg, G. (author), Veldhuis, L.L.M. (author)This experimental study focuses on the aerodynamic interaction effects that occur between an over-the-wing (OTW) propeller and a wing boundary-layer. An OTW propeller is positioned above the hinge-line of a wing featuring a plain flap. The measurements are carried out with and without axial pressure gradients by deflecting the flap and by...conference paper 2019
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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 Boundary Layer Ingestion (BLI) embedded propulsion systems. Such engine configurations can suffer from inlet flow distortions and ingestion of turbulence at the fan plane with consequent impact on both broadband and tonal fan...conference paper 2019
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Rego, Leandro (author), Avallone, F. (author), Ragni, D. (author), Casalino, D. (author), van der Velden, Wouter (author)An investigation of the effects of free-stream on jet-installation noise is performed using a numerical solver based on the lattice-Boltzmann method. In order to simulate a realistic configuration, a high-lift wing comprised by a main element and a deployed flap (MD30P30N) is placed in the vicinity of a dual-stream engine (GE90-94B). The engine...conference paper 2019
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Rubio Carpio, A. (author), Avallone, F. (author), Ragni, D. (author), Snellen, M. (author), van der Zwaag, S. (author)Turbulent boundary layer trailing-edge noise scattered by a NACA0018 airfoil equipped with 3D printed perforated trailing-edge inserts, i.e. with straight cylindrical channels connecting the two sides of the airfoil, is investigated. The inserts have different permeability in order to assess the effect of this property on broadband noise...conference paper 2019
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Teruna, C. (author), Manegar, F.A. (author), Avallone, F. (author), Casalino, D. (author), Ragni, D. (author), Rubio Carpio, A. (author), Carolus, Thomas (author)This manuscript presents a numerical investigation of the turbulent boundary layer-trailing edge (TBL-TE) noise reduction with an open-cell porous material. The implementation of the porous media is verified by emulating a facility for characterizing the flow resistivity of the porous material. Subsequently, the porous media is applied on the...conference paper 2019
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Arcondoulis, Elias J. G. (author), Ragni, D. (author), Rubio Carpio, A. (author), Avallone, F. (author), Liu, Yu (author), Yang, Yannian (author), Li, Zhiyong (author)Porous coated cylinders have been shown to reduce the vortex shedding tone and broadband noise of a bare cylinder placed in uniform flow within specific Reynolds number regimes. The processes by which the vortex shedding and thus tone suppression take place are still uncertain despite numerous numerical and experimental studies. It is understood...conference paper 2019
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Ye, Q. (author), Avallone, F. (author), Ragni, D. (author), Choudhari, Meelan (author), Casalino, D. (author)Surface roughness elements are often used to force laminar to turbulent transition during aerodynamic and aeroacoustic experiments in wind tunnels. The statistical features and frequency content of the forced turbulent boundary layer can influence the far-field trailing edge noise. To study this dependence, boundary layer transition induced by...conference paper 2019