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Mourão Bento, H.F. (author), VanDercreek, Colin (author), Avallone, F. (author), Ragni, D. (author), Sijtsma, P. (author), Snellen, M. (author)Aeroacoustic tests in closed wind tunnels are affected by reflections in the tunnel circuit and background noise. Reflections can be mitigated by lining the tunnel circuit. The present study investigates if lining exclusively the most accessible segment of a closed wind tunnel circuit, in particular the test section, is an approach which...conference paper 2023
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Van der Grift, R.C. (author), Snellen, M. (author), Simons, D.G. (author)Accurate modelling of aircraft noise in different weather conditions is crucial for the reliability of noise predictions and their application worldwide. In best-practice aircraft noise models, such as Doc.29, the change in expected sound level on the ground due to changing atmosphere is modelled with a simplified propagation calculation. The...conference paper 2023
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Sijtsma, P. (author), Brouwer, Harry (author), Snellen, M. (author)The fan-stator stage of turbofan engines is one of the main regions of broadband noise generation. The trend of increasing bypass ratios will make fan-stator broadband noise even more significant, as jet noise will decrease and nacelles will become shorter, thus leaving less space for liners. Within the fan-stator stage there are several...conference paper 2023
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Luesutthiviboon, S. (author), Meirelles Pereira, L. (author), Ragni, D. (author), Avallone, F. (author), Snellen, M. (author)The authors would like to provide the following corrections and clarifications to the article titled “Aeroacoustic Benchmarking of Trailing-edge Noise from a NACA 633–018 Airfoil with Trailing-edge Serrations” which has been published in the AIAA Journal Vol. 61, No. 1, and can be accessed online via https://doi.org/10.2514/1.J061630. The first...journal article 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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Bai, Q. (author), Mestdagh, S.M.F. (author), Snellen, M. (author), Simons, D.G. (author)To facilitate the conservation of seafloor habitats and planning of offshore activities, there is a growing need for mapping marine benthos in an effective and efficient way. Acoustic data acquired by multi-beam echosounders (MBES) have been extensively used for large-scale and high-resolution seafloor characterization. A deeper understanding of...journal article 2023
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Altena, A. (author), Luesutthiviboon, S. (author), de Croon, G.C.H.E. (author), Snellen, M. (author), Voskuijl, M. (author)Due to technological advances in the drone industry, security threats induced by unmanned aerial vehicles (UAVs) are becoming more relevant. Fast and accurate localisation systems need to be designed. One approach is localisation of UAVs by their sound using acoustic techniques. So far, a systematic performance assessment of acoustic...conference paper 2023
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Bai, Q. (author), Mestdagh, S.M.F. (author), Snellen, M. (author), Amiri Simkooei, A. (author)Acoustic classification using single-beam and multi-beam echosounders has been widely applied in characterizing seabed sediments. Although previous studies have shown a better discrimination of fine and coarse sediments using multi-spectral echosounder data, analysis regarding comprehensive seabed sediment properties is still needed. In this...conference paper 2023
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Afrasteh, Y. (author), Slobbe, D.C. (author), Sacher, M. (author), Verlaan, M. (author), Klees, R. (author), Guarneri, H. (author), Keyzer, L.M. (author), Pietrzak, J.D. (author), Snellen, M. (author)All realizations of the European Vertical Reference System (EVRS) computed so far are solely based on geopotential differences obtained by spirit leveling/gravimetry. As such, there are no direct connections between height benchmarks separated by large water bodies. In this study, such connections are added by means of model-based...journal article 2023
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Mestdagh, S.M.F. (author), Bai, Q. (author), Snellen, M. (author)Detailed knowledge of both the sedimentological and ecological characteristics of the seafloor is essential when undertaking bottom-disturbing activities, but can be a challenge to obtain. Through backscatter data at different frequencies, collected with a multi-spectral multi-beam sonar, information on the structure of both the sediment...conference paper 2023
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Guarneri, H. (author), Verlaan, M. (author), Slobbe, D.C. (author), Veenstra, J. (author), Zijl, F. (author), Pietrzak, J.D. (author), Snellen, M. (author), Keyzer, L.M. (author), Afrasteh, Y. (author), Klees, R. (author)Both empirical and assimilative global ocean tidal models are significantly more accurate in the deep ocean than in shelf and coastal waters. In this study, we answered whether this is due to the quality of the models used to reduce tide and surge or the general approach to treat tide and surge as two separate components of the water level...journal article 2023
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Afrasteh, Y. (author), Slobbe, D.C. (author), Verlaan, M. (author), Klees, R. (author), Guarneri, H. (author), Keyzer, L.M. (author), Pietrzak, J.D. (author), Sacher, M. (author), Snellen, M. (author), Zijl, F. (author)The main objective of this study is to develop and analyze an empirical noise model for model-derived coastal summer mean water levels (SMWLs) and use that to obtain a more realistic quality impact of combining hydrodynamic leveling and Unified European Leveling Network (UELN) data in realizing the European Vertical Reference System (EVRS)....journal article 2023
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Domingos de Azevedo Quadros, F. (author), van Loo, Marijn (author), Snellen, M. (author), Dedoussi, I.C. (author)Excess nitrogen deposition from anthropogenic sources of atmospheric emissions, such as agriculture and transportation, can have negative effects on natural environments. Designing effective conservation efforts requires knowledge of the contribution of individual sectors. This study utilizes a global atmospheric chemistry-transport model to...journal article 2023
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Makaveev, M.K. (author), Snellen, M. (author), Smeur, E.J.J. (author)This paper puts forward a novel design for an airspeed instrument aimed at small fixed-wing tail-sitter unmanned aerial vehicles. The working principle is to relate the power spectra of the wall-pressure fluctuations beneath the turbulent boundary layer present over the vehicle’s body in flight to its airspeed. The instrument consists of two...journal article 2023
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Domingos de Azevedo Quadros, F. (author), Snellen, M. (author), Dedoussi, I.C. (author)Aircraft emitted oxides of nitrogen (NOx) contribute both to climate change and air quality degradation. The trend of higher gas temperatures, caused by engine design choices seeking lower fuel consumption and achieve more complete combustion, has the adverse effect of increasing NOx formation, which might however be compensated by improved...conference paper 2022
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Vieira, A.E. (author), von den Hoff, B. (author), Snellen, M. (author), Simons, D.G. (author)The contribution of the engine and the airframe to the total noise generated by an aircraft varies with the operating conditions. Semi-empirical models are able to account for such variations but require detailed engine and airframe data as input that is not readily available for most aircraft types and operations. This hinders the validation of...journal article 2022
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Mohammadloo, Tannaz H. (author), Geen, Matt (author), Sewada, Jitendra S. (author), Snellen, M. (author), Simons, D.G. (author)Realistic predictions of the contribution of the uncertainty sources affecting the quality of the bathymetric measurements prior to a survey is of importance. To this end, models predicting these contributions have been developed. The objective of the present paper is to assess the performance of the bathymetric uncertainty prediction model for...journal article 2022
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Merino Martinez, R. (author), VanDercreek, Colin (author), Snellen, M. (author)Aeroacoustic measurements with microphones in closed-section wind tunnels are typically hampered by the pressure fluctuations of the turbulent boundary layer (TBL) on the tunnel's walls, ceiling, or floor, where phased microphone arrays are usually mounted. This paper evaluates the performance of several advanced acoustic imaging methods that...conference paper 2022
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De Breuker, R. (author), Benedictus, R. (author), Bisagni, C. (author), Boneschansker, I. (author), Melkert, J.A. (author), Snellen, M. (author), Veldhuis, L.L.M. (author), Verdegaal, F.M. (author), Visser, P.N.A.M. (author), Werij, H.G.C. (author)The Faculty of Aerospace Engineering is one of eight faculties at Delft University of Technology. It is one of the most comprehensive academic and innovation communities worldwide focusing on aerospace engineering. Its 120 professors and 70 researchers are mentoring and teaching around 2,800 BSc/MSc students and more than 350 PhD candidates...journal article 2022
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Merino Martinez, R. (author), von den Hoff, B. (author), Morata, David (author), Snellen, M. (author)Complex test models in aeroacoustic experiments often present an arrangement of noise sources within a three–dimensional space. Planar microphone array normally have difficulties in separating sound sources in the direction normal to the array plane due to their poorer spatial resolution in this direction. This paper evaluates the benefits of...conference paper 2022