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Rol, M.P. (author), Nijboer, Ronald (author), Yarovoy, Alexander (author)Electromagnetic (EM) waves propagate through the atmosphere where they are refracted depending on the composition of the atmosphere. This refraction highly influences the propagation of the EM-waves. Certain atmospheric conditions can cause EM-waves to get trapped within a duct. In these ducts blind zones may occur, where there is no EM-wave...conference paper 2022
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Jiang, Hanjie (author), Zhou, Y. (author), Ho, H.W. (author)Urban air mobility is a relatively new concept that has been proposed in recent years as a means of transporting passengers and goods in urban areas. It encompasses a diverse range of Vertical TakeOff and Landing (VTOL) vehicles that function more like passenger-carrying drones for on-demand transportation. Among them, the car-like VTOL is...journal article 2022
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Liu, Zhengxuan (author), Xing, Chaojie (author), Zeng, Chao (author), Zhou, Yuekuan (author)Geothermal energy (GE), as an ideal renewable resource for building cooling/heating with stability and abundance in energy supply, has been widely exploited in developing countries. The common utilization forms of GE mainly include the ground source heat pump (GSHP), underground duct system (UDS), and abandoned wells energy (AWE) system....book chapter 2022
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Avallone, F. (author), Ragni, D. (author), Casalino, D. (author)Lattice-Boltzmann Very-Large-Eddy Simulations of two Diffuser-Augmented Wind Turbines are carried out to investigate the effect of the tip-clearance (TC) ratio on both the flow field and the far-field noise. The DonQi® wind turbine, a three blades ducted rotor with nominal TC of 2.5%, is chosen as reference test case. The second configuration...journal article 2020
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Dighe, V.V. (author), Avallone, F. (author), van Bussel, G.J.W. (author)Ducted Wind Turbines (DWTs) can be used for energy harvesting in urban areas where non-uniform inflows might be the cause of aerodynamic and acoustic performance degradation. For this reason, an aerodynamic and aeroacoustic analysis of DWTs in yawed inflow condition is performed for two duct geometries: a baseline commercial DWT model, DonQi®...journal article 2020
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Dighe, V.V. (author)Ducted Wind Turbines (DWTs) are one of the many concepts that have been proposed to improve the energy extraction from wind in comparison to bare wind turbines. In reviewing the DWT studies, investigations based on the combined use of theoretical, computational, and experimental techniques have been presented. Although indicated in these studies...doctoral thesis 2020
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Modesti, D. (author)We carry out a priori tests of linear and nonlinear eddy viscosity models using direct numerical simulation (DNS) data of square duct flow up to friction Reynolds number Re <sub>τ</sub>= 1055. We focus on the ability of eddy viscosity models to reproduce the anisotropic Reynolds stress tensor components a<sub>ij</sub> responsible for...journal article 2020
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Malgoezar, A.M.N. (author), Vieira, A.E. (author), Snellen, M. (author), Simons, D.G. (author), Veldhuis, L.L.M. (author)Ducted propellers are an interesting design choice for unmanned aerial vehicle (UAV) concepts due to a potential increase of the propeller efficiency. In such designs, it is commonly assumed that introducing the duct also results in an overall noise reduction. The objective of this work is to experimentally analyze and quantify noise of a...review 2019
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Küçükosman, Y.C. (author)The integration of wind turbines into urban environments is a challenging task due to the reduced wind speed and high turbulence levels caused by the surface resistance, as well as limited spacing. If a specific building arrangement is explored, an improve ment in wind speed can be obtained. This would be especially beneficial for tall build...doctoral thesis 2019
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Dighe, V.V. (author), De Oliveira Andrade, G.L. (author), Avallone, F. (author), van Bussel, G.J.W. (author)The complex aerodynamic interactions between the rotor and the duct has to be accounted for the design of ducted wind turbines (DWTs). A numerical study to investigate the characteristics of flow around the DWT using a simplified duct–actuator disc (AD) model is carried out. Inviscid and viscous flow calculations are performed to understand...journal article 2019
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Rajpal, D. (author), De Breuker, R. (author), Timmermans, H (author), Lammen, Wim (author), Torrigiani, F. (author)High aspect ratio strut braced aircraft can significantly reduce the induced drag. The inherent anisotropic behaviour of the composite material along with their weight saving potential can improve the performance of the aircraft during the flight. Thus, a composite strut braced aircraft is one of the promising candidates to achieve the targets...conference paper 2018
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Vos, Roelof (author), Hoogreef, M.F.M. (author)Three regional transport aircraft of different configuration are synthesized for the same design specification using an automated design routine. The first aircraft features wing-mounted propellers, the second aircraft features propellers mounted on the horizontal tail plane, while the last configuration replaces the horizontal and vertical tail...conference paper 2018
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Muhammad Iqbal, M.A.F. (author), Trajanovski, S. (author), Kuipers, F.A. (author)Spatially-close network fibers have a significant chance of failing simultaneously in the event of man-made or natural disasters within their geographic area. Network operators are interested in the proper detection and grouping of any existing spatially-close fiber segments, to avoid service disruptions due to simultaneous fiber failures....conference paper 2016
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Tang, J. (author), Avallone, F. (author), van Bussel, G.J.W. (author)This study presents an experimental investigation on a diffuser augmented wind turbine (DAWT). A screen mesh is used to simulate the energy extraction mechanisms of a wind turbine in experiment. Different screen porosities corresponding to different turbine loading coefficients are tested. Measurements of the axial force and of the velocity...journal article 2016
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Satyavada, H. (author), Babuska, R. (author), Baldi, S. (author)The field of energy efficiency in buildings offers challenging opportunities from a control point of view. Heating, Ventilation and Air-Conditioning (HVAC) units in buildings must be accurately controlled so as to ensure the occupants' comfort and reduced energy consumption. While the existing HVAC models consist of only one or a few HVAC...conference paper 2016
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- Hutchison, Suzanne (author), Steen, Sverre (author), Sanghani, Abhishek (author) conference paper 2013
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Pantazopoulou, P. (author), Drikakis, D. (author)The paper presents a computational study of acoustic scattering from a cylindrical duct into uniform flow. The sound source is a fan inside the duct responsible for generating a spinning acoustic mode. The sound pressure scattering behaviour as function of the fan tip speed and mean flow velocity, as well as the acoustic modes propagation inside...conference paper 2006
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Huang, X. (author), Ma, Z. (author), Zhang, X. (author)This paper outlines the method of a block-structured adaptive mesh refinement (AMR) and its application to the computation of noise radiation from a realistic engine exhaust geometry with flow. The computational model described allows acoustic waves, propagating inside the bypass duct of a generic aircraft engine, to be admitted into a...conference paper 2006
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Parente, C.A. (author), Rademaker, E.R. (author), Sarin, S.L. (author)From the in-flight measured circumferential modal spectra of the Rolls-Royce Tay 650 engine mounted on the Fokker 100, it was found that the sound field propagating upstream in the inlet is strongly modulated by intercostal hard-walled strips in the lined area, the non-cylindrical geometry of the duct, and the non-axisjnmnetric flow velocity...report 1996
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Sijtsma, P. (author)A theory is presented to calculate acoustic modes in a circular flow duct lined with porous material. The porous material is divided into annular segments by a rigid structure, which prevents axial sound propagation from one segment into the other. Single modes cannot exist in such a configuration, but it is shown that approximate solutions of...report 1996
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