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Vieira, A.E. (author), Mehmood, Umair (author), Merino Martinez, R. (author), Snellen, M. (author), Simons, D.G. (author)The capacity of airports is limited due to the negative community response to noise. Traditional metrics, such as the A-weighted maximum sound pressure level (Lp;A;max), indicate the overall noise generated by an aircraft flyover but do not provide any information on tonal components or frequency variations in time that are known to affect...conference paper 2019
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VanDercreek, Colin (author), Sijtsma, P. (author), Snellen, M. (author), Ragni, D. (author), Avallone, F. (author), Simons, D.G. (author)A mathematical model is proposed that evaluates acoustic propagation of turbulent boundary layer waves on top of a cavity enclosing a microphone. The goal is to optimize these cavity geometries to improve the signal-to-noise ratio of acoustic measurements. This model predicts the attenuation of the turbulent boundary layer fluctuations...conference paper 2019
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Luesutthiviboon, S. (author), Avallone, F. (author), Ragni, D. (author), Snellen, M. (author)An analytical method for predicting the steady pressure distribution on porous airfoils with a prescribed porosity distribution is assessed through comparison of its lift prediction with experimental data. The method is based on the thin-airfoil formulation. The no-slip boundary condition of the airfoil surface has been replaced by the Darcy’s...conference paper 2019
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Merino Martinez, R. (author), Pieren, R.D. (author), Snellen, M. (author), Simons, D.G. (author)Noise emissions from wind turbines are one of the main issues that the wind energy industry must deal with nowadays. Strict noise regulations often prevent wind turbines to operate at maximum power conditions, causing large losses of power production and, hence, of revenue. Several noise reduction measures have been proposed so far, but the...conference paper 2019
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Luesutthiviboon, S. (author), Malgoezar, A.M.N. (author), Snellen, M. (author), Sijtsma, P. (author), Simons, D.G. (author)Beamforming performance can be improved in two ways: optimizing the location of microphones on the acoustic array and applying advanced beamforming algorithms. In this study, the effects of the two approaches are studied. An optimization method is developed to optimize the location of microphones for an acoustic array used in an open-jet...conference paper 2018
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Beaudoin, Jonathan (author), Renoud, Weston (author), Mohammadloo, Tannaz H. (author), Snellen, M. (author)In a world of high precision sensors, one of the few remaining challenges in multibeam echosounding is that of refraction-based uncertainty. A poor understanding of oceanographic variability or a poor choice of equipment can lead directly to poor quality bathymetric data. Post-processing software tools have existed for some time to allow data...conference paper 2018
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Merino Martinez, R. (author), Sijtsma, P. (author), Snellen, M. (author)Most acoustic imaging methods assume the presence of point sound sources and, hence, fail to correctly estimate the sound emissions of distributed sound sources (such as trailing– edge noise). In this contribution, three integration techniques are suggested to overcome this issue based on models considering a single point source, a line source...conference paper 2018
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Vieira, A.E. (author), Malgoezar, A.M.N. (author), Snellen, M. (author), Simons, D.G. (author)The shielding of engine noise by the airframe of an aircraft is considered an effective way of reducing noise levels on the ground. Noise shielding in conventional aircraft is mainly due to the presence of the wings and most model predictions of full-scale aircraft neglect the effect of the airfoil curvature. The engine is typically simpliffied...conference paper 2018
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Merino Martinez, R. (author), Neri, Eleonora (author), Snellen, M. (author), Kennedy, John (author), Simons, D.G. (author), Bennett, Gareth J. (author)The noise emissions of a full-scale nose landing gear, measured in a wind tunnel and obtained from computational simulations, are compared with those of three regional aircraft types recorded in flyover measurements. The results from these three approaches are also compared with the predictions of two airframe noise models (Fink and Guo). The...conference paper 2018
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Manjunath, P. (author), Avallone, F. (author), Casalino, D. (author), Ragni, D. (author), Snellen, M. (author)Acoustic liners are widely used as noise suppression devices, for example in aircraft engines. The effectiveness of the liners is measured through the impedance. In the present study, using a lattice-Boltzmann solver, the response of two liner geometries to grazing acoustic waves is examined. The two geometries have porosity equal to 0.99%...conference paper 2018
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Merino Martinez, R. (author), Sanders, Martinus P.J. (author), Caldas, Luciano C. (author), Avallone, F. (author), Ragni, D. (author), de Santana, Leandro D. (author), Snellen, M. (author), Simons, D.G. (author)Microphone arrays are useful measurement devices for estimating the location and strength of sound sources. Numerous comparative studies have been conducted regarding the performance of acoustic imaging methods in the past, but literature lacks of a systematic investigation on the role of the hardware on the measurements. This research...conference paper 2018
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- Merino Martinez, R. (author), Neri, Eleonora (author), Snellen, M. (author), Kennedy, J (author), Simons, D.G. (author), Bennett, Gareth J. (author) conference paper 2017
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Mohammadloo, Tannaz H. (author), Tengku Ali, T.A. (author), Snellen, M. (author), Koop, L. (author), Gaida, T.C. (author), Simons, D.G. (author)Knowing the morphology and sediment composition of the seabed is of high importance for various applications. In this contribution, the repeatability of acoustic seafloor classification (ASC) results obtained from MBES backscatter value is investigated. The unsupervised classification algorithm based on Principal Component Analysis has been...conference paper 2017
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Mohammadloo, Tannaz H. (author), Snellen, M. (author), Simons, D.G. (author)The most recent generation multi-beam echosounders (MBES) allows to transmit Frequency Modulated (FM) signals, in addition to the more conventional Continuous Wave (CW) pulses. In this contribution, the effect of using these FM pulses for bathymetric measurements is investigated. Advantage of using FM signals is that measurements can be taken at...conference paper 2017
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- Mohammadloo, Tannaz H. (author), Snellen, M. (author), Simons, D.G. (author), Dierikx, Ben (author), Bicknese, Simon (author) conference paper 2017
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- Sarradj, Ennes (author), Herold, Gert (author), Sijtsma, P. (author), Merino Martinez, R. (author), Malgoezar, A.M.N. (author), Snellen, M. (author), Geyer, Thomas F. (author), Bahr, Christopher J. (author), Porteous, Ric (author), Moreau , Danielle J. (author), Doolan, Con J. (author) conference paper 2017
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- Sijtsma, P. (author), Merino Martinez, R. (author), Malgoezar, A.M.N. (author), Snellen, M. (author) conference paper 2017
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- Simons, D.G. (author), Snellen, M. (author), Merino Martinez, R. (author), Malgoezar, A.M.N. (author) conference paper 2017
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- Merino Martinez, R. (author), Rubio Carpio, A. (author), Avallone, F. (author), Ragni, D. (author), Snellen, M. (author), van der Zwaag, S. (author) conference paper 2017
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Vieira, A.E. (author), Snellen, M. (author), Simons, D.G. (author)The shielding of engine noise by the aircraft wings and fuselage can lead to a significant reduction on perceived noise on ground. Most research on noise shielding is focused on BlendedWing Body (BWB) configurations because of the large dimension of the fuselage. However, noise shielding is also considered relevant in conventional tube and...conference paper 2017