Bibliographies thématiques / Aeroacoustic noise

Littérature scientifique sur le sujet « Aeroacoustic noise »

Auteur : Grafiati
Publié le 25 mai 2024

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Articles de revues sur le sujet "Aeroacoustic noise"

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Fabrizi, Carlo. « Computational Aeroacoustic Analysis of a Rolling Tire ». Tire Science and Technology 44, no 4 (1 octobre 2016) : 262–79. http://dx.doi.org/10.2346/tire.16.440403.

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ABSTRACT Road traffic is one of the major sources of noise in modern society. Consequently, the development of new vehicles is subject to increasingly stringent guidelines in terms of noise emissions. The main noise sources of common road vehicles are the engine, the transmission, the aerodynamics, and the tire-road interaction. The latter becomes dominant between 50 and 100 km/h, speeds typical of urban and extra-urban roads. The noise that arises from the tire-road interaction is the combination of structural vibration and aeroacoustics phenomena that create and amplify or reduce the sound emitted from the tire. The aim of the numerical analysis presented in this study is to investigate the aeroacoustic noise-generation mechanisms of the tire and at the same time provide a tool to develop a low-noise tire. The work is divided into two parts: analysis of the steady aerodynamics and the unsteady aeroacoustic analysis. In the first part, the numerical solution of the Navier-Stokes equation allows us to screen aerodynamic phenomena, such as separations or jet streams that can produce noise. In the second part, these aspects are analyzed in greater detail by means of aeroacoustic analogies, confirming the capability of the numerical tool to provide suggestions for the development of quieter tires.
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Joshi, Arnav, Mustafa M. Rahman et Jean-Pierre Hickey. « Recent Advances in Passive Acoustic Localization Methods via Aircraft and Wake Vortex Aeroacoustics ». Fluids 7, no 7 (29 juin 2022) : 218. http://dx.doi.org/10.3390/fluids7070218.

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Passive acoustic aircraft and wake localization methods rely on the noise emission from aircraft and their wakes for detection, tracking, and characterization. This paper takes a holistic approach to passive acoustic methods and first presents a systematic bibliographic review of aeroacoustic noise of aircraft and drones, followed by a summary of sound generation of wing tip vortices. The propagation of the sound through the atmosphere is then summarized. Passive acoustic localization techniques utilize an array of microphones along with the known character of the aeroacoustic noise source to determine the characteristics of the aircraft or its wake. This paper summarizes the current state of knowledge of acoustic localization with an emphasis on beamforming and machine learning techniques. This review brings together the fields of aeroacoustics and acoustic-based detection the advance the passive acoustic localization techniques in aerospace.
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Vouros, Stavros, Ioannis Goulos, Calum Scullion, Devaiah Nalianda et Vassilios Pachidis. « Impact of Tip-Vortex Modeling Uncertainty on Helicopter Rotor Blade–Vortex Interaction Noise Prediction ». Journal of the American Helicopter Society 66, no 1 (1 janvier 2021) : 1–13. http://dx.doi.org/10.4050/jahs.66.012005.

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Free-wake models are routinely used in aeroacoustic analysis of helicopter rotors; however, their semiempiricism is accompanied with uncertainty related to the modeling of physical wake parameters. In some cases, analysts have to resort to empirical adaption of these parameters based on previous experimental evidence. This paper investigates the impact of inherent uncertainty in wake aerodynamic modeling on the robustness of helicopter rotor aeroacoustic analysis. A free-wake aeroelastic rotor model is employed to predict high-resolution unsteady airloads, including blade–vortex interactions. A rotor aeroacoustics model, based on integral solutions of the Ffowcs Williams–Hawkings equation, is utilized to calculate aerodynamic noise in the time domain. The individual analytical models are incorporated into an uncertainty analysis numerical procedure, implemented through nonintrusive Polynomial Chaos expansion. The potential sources of uncertainty in wake tip-vortex core growth modeling are identified and their impact on noise predictions is systematically quantified. When experimental data to adjust the tip-vortex core model are not available the uncertainty in acoustic pressure and noise impact at observers dominated by blade–vortex interaction noise can reach up to 25% and 3.50 dB, respectively. A set of generalized uncertainty maps is derived, for use as modeling guidelines for aeroacoustic analysis in the absence of the robust evidence necessary for calibration of semiempirical vortex core models.
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Ragni, Daniele, Francesco Avallone et Damiano Casalino. « Measurement techniques for aeroacoustics : from aerodynamic comparisons to aeroacoustic assimilations ». Measurement Science and Technology 33, no 6 (9 mars 2022) : 062001. http://dx.doi.org/10.1088/1361-6501/ac547d.

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Abstract Sustainability has encouraged studies focusing on lowering the aeroacoustic impact of new aerodynamically optimized mechanical systems for several applications in wind-energy, aviation, automotive and urban air-mobility. The deployment of effective noise-reduction strategies starts with a deep understanding of the underlying mechanisms of noise generation. To elucidate the physics behind the onset of aerodynamic sources of sound, experimental techniques used for aerodynamic purposes have been combined with acoustic measurements. In the last decades, new experimental post-processing techniques have additionally been developed, by leveraging aeroacoustic analogies in a new multi-disciplinary framework. New approaches have been proposed with the intent of translating near-field velocity and pressure information into sound. The current review describes how such breakthroughs have been achieved, briefly starting from a historical overview, to quickly bridge to the measurement techniques and the facilities employed by the scientific community. Being the measurement principles already reported in the literature, this review only focuses on the most relevant studies trying to relate the near-field information to the perceived sound in the far-field. Aspects related to the uncertainty of the measurement techniques will be thus very briefly discussed, together with their relation to the background noise of the testing facilities, including acoustic reflections/refractions, and issues related to the instrumentation.
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Perugini, Carlo Alberto, Ugo Riccio, Antonio Torluccio, Rouven Mohr, Reinhard Blumrich et Andreas Wagner. « An Efficient Hybrid Computational Process for Interior Noise Prediction in Aeroacoustic Vehicle Development ». INTER-NOISE and NOISE-CON Congress and Conference Proceedings 266, no 2 (25 mai 2023) : 829–38. http://dx.doi.org/10.3397/nc_2023_01_1120.

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Numerical methodologies for aeroacoustic analyses are increasingly crucial for car manufacturers to optimize the effectiveness of vehicle development. In the present work, a hybrid numerical tool based on the combination of a delayed detached-eddy simulation and a finite element model, which relies on the Lighthill's acoustic analogy and the acoustic perturbation equations, is presented. The computational aeroacoustics is performed by the software OpenFOAM and Actran, concerning respectively the CFD and the FEM. The aeroacoustic behavior of the SUV Lamborghini Urus at a cruising speed of 140 km/h has been investigated. The main aerodynamic noise phenomena occurring in the side mirror region in a frequency range up to 5 kHz are discussed. The numerical simulations have been verified against the measurements performed in the aeroacoustic wind tunnel of the University of Stuttgart, operated by FKFS. The predicted exterior noise propagation into the far field has been validated by comparing the sound pressure level with the experimental data measured by exterior microphones, which were located outside the turbulent region beside the wake of the side mirror. Furthermore, the noise transmission into the cabin through the side window has been modeled. Simulation results have been validated by means of interior microphones installed on the driver seat. Both the exterior and the interior noise predictions show very good correlations with experiments. Lastly, a comprehensive investigation of the most critical aeroacoustic sources has been carried out. The numerical tool has been proven to be in good accordance with the microphone array with respect to the distribution of the sound pressure level in the proximity of the side mirror. Besides, the main vortex structures involved in the generation mechanisms of wind noise have been investigated by a CFD analysis. The entire CAA process has been proven to be accurate and suitable for combined analysis between the generation mechanisms of wind noise and the resulting transfer into the interior cabin to the driver's ear as well.
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Klimczyk, Witold, et Adam Sieradzki. « RANS-Based Aeroacoustic Global Sensitivity Study and Optimization of UAV Propellers ». Aerospace 10, no 3 (20 mars 2023) : 306. http://dx.doi.org/10.3390/aerospace10030306.

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Modeling of Unmanned Aerial Vehicles (UAV) propellers in a global, multidisciplinary aeroacoustic optimization was investigated. The modeling consists of three aspects: geometry, aerodynamics, and aeroacoustics. Firstly, a parametric geometry model was established using chord, twist, and sweep distributions along the radius, defined by splines to ensure smoothness. Additionally, airfoil parameters including maximum camber and its position, as well as the position of maximum thickness, were added. Secondly, a blade geometry-resolved aerodynamic model based on steady RANS was established. A two-equation SST turbulence model was used for compressible flow with periodic boundary conditions. Thirdly, an aeroacoustic model for far-field tonal noise calculation was defined, based on the Ffowcs Williams and Hawkings analogy and a RANS solution. A global sensitivity analysis was performed to establish the importance of individual design variables. Consequently, surrogate modeling-based optimization strategy was devised to efficiently establish Pareto front of propeller geometries in multi-objective aeroacoustic optimization.
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Schoder, Stefan, et Manfred Kaltenbacher. « Hybrid Aeroacoustic Computations : State of Art and New Achievements ». Journal of Theoretical and Computational Acoustics 27, no 04 (décembre 2019) : 1950020. http://dx.doi.org/10.1142/s2591728519500208.

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This paper collects the state of the art and the tremendous progress that has been made in hybrid modeling of aeroacoustic sound. Hybrid modeling is defined such that flow and acoustics are modeled separate and connected by an aeroacoustic model. The contributions will be classified with respect to the aeroacoustic models being developed, covering Lighthill’s analogy, Ffowcs Williams and Hawkings, vortex sound, linearized Euler equations (LEE), and different perturbation equations modeling flow induced sound. Within each topic, specific applications, such as jet noise, aircraft noise, ground mobility, noise, fan noise and human phonation, are covered. We focus on the accomplishments and provide the authors’ contribution to aeroacoustic research. Eventually, a concise summary of the different methods and their capabilities is included.
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Cai, Jian Cheng, Yong Hai Zhang et Shuang Li Long. « Computational Estimation of Fan Casing Noise at Blade Passing Frequency Component Noise ». Applied Mechanics and Materials 184-185 (juin 2012) : 95–100. http://dx.doi.org/10.4028/www.scientific.net/amm.184-185.95.

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This paper studies both vibroacoustics and aeroacoustics of a centrifugal fan casing; the aim of this study is to explore a methodology to make quantitative predictions of fan casing noise. The spectra of the fan noise and casing vibration were firstly presented; discrete components related to the rotational frequency protrude in the spectra, especially the blade passing frequency (BPF). Computational fluid dynamics (CFD) technique was used to obtain the three-dimensional unsteady turbulent internal flow. Attention was paid to the pressure fluctuations on the volute wall; the shapes of pressure fluctuation were nearly sinusoidal in nature, with the BPF as the primary frequency. On the vibroacoustic side, Fast Fourier Transform (FFT) was applied to the time series of pressure fluctuations to extract the BPF component. A finite element analysis (FEA) model of the casing structure was constructed, and was validated by experimental modal analysis. The harmonic dynamic response of the casing structure was calculated with the BPF pressure fluctuation component as the excitation. The vibration results were then taken as the velocity (Neumann) boundary condition for the noise radiation model which was built in boundary element method (BEM), and the sound radiation was calculated. On the aeroacoustic side, the BPF component of pressure fluctuations was modeled as acoustic dipole source, and sound radiation was also solved by BEM. Results show that the sound pressure level (SPL) of vibroacoustics is fairly small compared to the aeroacoustic counterpart. This study shows that CFD, FEA together with BEM can be used to numerically predict BPF casing noise of turbomachinery successfully.
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Staron, Domenic, Matthias Riegel, Reinhard Blumrich et Andreas Wagner. « Aeroacoustic Vehicle Development Method Considering Realistic Wind Conditions ». INTER-NOISE and NOISE-CON Congress and Conference Proceedings 266, no 2 (25 mai 2023) : 858–66. http://dx.doi.org/10.3397/nc_2023_01_1123.

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The aeroacoustic development of vehicles is still mainly carried out in wind tunnels under steady flow conditions, although the real situation is different. However, as discussed in several earlier publications, a vehicle experiences unsteady, turbulent flow on road, which results for example from natural wind, wakes of other vehicles, or obstacles at the roadside in combination with side wind. The resulting temporal variations of the wind noise inside the cabin affect the passengers' comfort and safety through fatigue. To be able to also consider the unsteady aeroacoustics in the vehicle development process, a comprehensive method has been developed that is presented in full for the first time in this paper. The on-road situation is simulated in a realistic and reproducible manner in the full-scale wind tunnel of the University of Stuttgart by means of an active turbulence generator, developed by FKFS. The turbulence generator allows to dynamically vary the flow angle with frequency components of up to 10 Hz. By comparing the unsteady wind noise for different flow situations and different vehicles, a flow scenario has been derived which leads to representative and meaningful aeroacoustic results. The measured temporal wind noise variations are investigated using modulation analysis, which has been adapted to show only relevant information in a comprehensible way. Finally, a psychoacoustic metric for rating the annoyance of unsteady, as well as steady, wind noise has been developed based on listening studies. The metric describes the subjective perception and allows evaluation and optimization of the aeroacoustic behavior specifically regarding the passengers' comfort. With this new method all wind noise aspects, steady as well as unsteady, can be determined and taken into account for vehicle development. The evaluation and comparison of vehicles and variants is comprehensive and is focused on the passengers' comfort.
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Ji, Chun Hui, et Zhan Qiang Liu. « Aeroacoustic Performance Evaluation of Milling Cutters Based on the Flow Field on the Cutter Surface ». Advanced Materials Research 188 (mars 2011) : 398–403. http://dx.doi.org/10.4028/www.scientific.net/amr.188.398.

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Many workers all over the world suffer significant hearing loss as well as psychological and physical stress as a result of exposure to high levels of aeroacoustic noise. Dipole sources are the major noise sources in aeroacoustic noise generation in rotating face milling cutters. A noise model based on the Ffowcs Williams-Hawkings Equation is used to predict aeroacoustic noise; the noise predicted was 2.5dB less than the experimental observations. Flow field of cutter surface was numerically simulated by the resolution of the Navier-Stokes equations (CFD) and five zones on cutter surface were founded to be the important noise source. The broadband noise spreads over a broad range of frequencies and contributes significantly to overall noise, but the discrete noise at the rotational frequency is usually higher and more detrimental to the body.
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Thèses sur le sujet "Aeroacoustic noise"

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Kingan, Michael Joseph. « Aeroacoustic noise produced by an aerofoil ». Thesis, University of Canterbury. Mechanical Engineering, 2005. http://hdl.handle.net/10092/6596.

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This thesis describes an investigation into the aeroacoustic noise produced by an aerofoil using experimental, computational and theoretical methods. Several different types of aeroacoustic noise generation mechanisms and the parameters which affect these mechanisms were identified and investigated. The aerofoils used' in this investigation all had chord lengths of 100mm and had a maximum thickness between 18mm and 30mm. Experimental testing was undertaken in the low noise wind tunnel in the Department of Mechanical Engineering at the University of Canterbury with the aerofoils mounted at the exit of the tunnel. Airflow speeds from 10m/s to 40m/s and a range of angles of incidence were investigated. A number of modifications were made to reduce the noise and improve the operation of the wind tunnel. Different methods of measuring the aeroacoustic noise produced by an aerofoil were also investigated. The theory of aeroacoustic noise generation is described and the effect of a scattering surface on the efficiency of these aeroacoustic noise sources was investigated. A number of different mechanisms by which an aerofoil produces aeroacoustic noise were identified. These mechanisms were divided into three main categories: (1) blunt trailing edge aerofoil noise (2) sharp trailing edge aerofoil noise and (3) stalled aerofoil noise. The effect of air temperature on the production of aeroacoustic noise was also investigated. It was found that in most instances air temperature would have little effect on aeroacoustic noise generation. An extensive study of the aeroacoustic noise produced by a number of different aerofoils was undertaken. Modelling of the airflow over the aerofoils was used to determine the mechanism by which aeroacoustic noise is produced. Several different aeroacoustic noise generation mechanisms were identified. Theoretical models were also used to model the aeroacoustic noise produced by the aerofoils. Several treatments to reduce the level of aeroacoustic noise produced by an aerofoil were investigated. The treatments reduced the aeroacoustic noise produced by an aerofoil with varying degrees of success. A method for measuring the aeroacoustic noise produced by car roof racks mounted on the roof of a vehicle using a relatively small wind tunnel was established. The noise level produced by a roof rack installed 011 the roof of a vehicle measured using this technique compared favourably with measurements made on a full vehicle in a large wind tunnel. The method shows promise as a low cost method of accurately measuring the aeroacoustic noise produced by roof racks installed on a vehicle roof.
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Boorsma, Koen. « Aeroacoustic control of landing gear noise using perforated fairings ». Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/66081/.

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A study was performed to investigate and optimize the application of perforated fairings for landing gear noise control. The sparse knowledge about this new subject has necessitated a more fundamental study involving a basic fairing-strut configuration, followed by wind tunnel tests on a simplified landing gear configuration incorporating perforated fairings. For the basic configuration, various exchangeable perforated half-cylindrical shells shrouding a circular cylinder were the subject of aerodynamic and acoustic tests. A qualitative and quantitative description has been given of the influence of perforated fairings on time averaged and unsteady flow and the related acoustics. The bled air through the shell prevents the formation of large scale vortices associated with the shell and thereby reduces low frequency noise. However, a test with a noisy H-beam replacing the circular cylinder has indicated that increasing porosity can result in adverse noise effects due to the bled mass flow washing the strut. Shearing flow past the perforate has been shown to create adverse self-noise of which both intensity and spectral content are dictated by the local velocity past the perforate. The application of perforated fairings to the simplified landing gear model reduces the low frequency noise introduced by the solid fairings to values below the baseline landing gear configuration in both side and ground view directions. Exposing the perforate outside the stagnation area does not yield extra noise reduction but introduces perforate self-noise. The synthesis of the conducted studies has shed new light on the application of perforated fairings for landing gear noise control. In particular the effects of porosity and perforation location have been clarified. However more research is needed for further optimization of these parameters.
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Yardibi, Tarik. « Source localization and power estimation in aeroacoustic noise measurements ». [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0024868.

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Gea-Aguilera, Fernando. « Aerodynamic and aeroacoustic modelling of engine fan broadband noise ». Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/412640/.

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This thesis investigates simplified but representative configurations of the fan wake-OGV interaction noise, which is a major source of engine fan broadband noise during take-off and landing. To this end, Computational AeroAcoustics (CAA) simulations are performed by using the Linearised Euler Equations (LEEs) and synthetic turbulence methods. An advanced digital filter method is presented to generate divergence-free synthetic turbulence with explicit control on the resulting turbulence spectrum. The method, which is based on the Random Particle-Mesh (RPM) method and synthetic eddy methods, is able to produce two- and three-dimensional fluctuating velocity fields of homogeneous isotropic and anisotropic turbulence. It is also shown that similar levels of simulation accuracy can be achieved by using digital filter and Fourier mode methods. Nevertheless, the advanced digital filter method provides enhanced performance in terms of computational cost (up to 3:9 times faster for two-dimensional simulations in this study). CAA simulations using the advanced digital filter method are performed to improve current understanding of leading edge noise from single aerofoils. For example, the method is used to examine the distortion of turbulent structures in the leading edge region. Furthermore, a comparison between numerical and experimental noise measurements in open-jet wind tunnel experiments indicate that the advanced digital filter method is capable of reproducing experimental results with an accuracy to within 3 dB. This thesis also presents a parameter study to assess the effects of moderately anisotropic turbulence, as occurs in the fan wakes, on leading edge noise from single aerofoils. Finally, fan wake modelling assumptions, such as cyclostationary variations in turbulent kinetic energy and integral length scale, are investigated using a cascade of thin aerofoils. Results indicate that broadband noise mainly depends on the circumferentially-averaged spectrum that is perceived by the cascade, and not on the instantaneous features of the fan wakes. A parameter study on cascade noise using isotropic turbulence is also included in this thesis, where variations in the vane count, aerofoil thickness, camber, mean flow Mach number, stagger angle, and inter-vane spacing are investigated. It is confirmed that the flat plate assumption provides sufficient accuracy for the frequency range in which engine fan broadband noise is relevant.
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Kiran, Amit. « Jet noise : aeroacoustic distribution of a subsonic co-axial jet ». Thesis, University of Warwick, 2008. http://wrap.warwick.ac.uk/3914/.

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The noise generated by aircraft can be easily heard by those living under the flight path of passenger or cargo carriers. It is considered an environmental pollutant and is treated as such by the International Civil Aviation Organization (ICAO) who monitor and review noise levels. The ICAO imposes substantial fines on those carriers who do not adhere to the decibel limitations. With the new limit or `stage' enforced in 2006, aircraft manufacturers (including jet engine manufacturers) are seeking ways to reduce the noise created by an aircraft. A 1/150th scale model, based on the exit geometry typically found on commercial jet engines, was designed and manufactured at Warwick. The laboratory jet flow conditions operated at 0.7 Mach. The work presented in this thesis looks at the noise generated in a subsonic, co- owing jet, with particular focus given to the distribution sound sources from 5 kHz to 80 kHz (0.375 St to 6.0 St). An acoustic mirror mounted on a motorized 3-way traverse measured radiated sound in the co-flowing jet to produce 2D sound source maps. This is done using combinations of smooth cowl and chevrons for the core and bypass nozzles. For frequencies less than 30 kHz, a reduction of noise was observed using the bypass chevron nozzle compared with the bypass smooth cowl nozzle. Laser Doppler Anemometry (LDA) was used to reveal the 2D flow dynamics of the jet, supporting the acoustic distribution results with velocity profiles of the flow. The change in the flow dynamics with different nozzle combinations is discussed and different regions of the flow were identified.
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Ghadiani, Ali. « Aerodynamics and aeroacoustic of sail masts ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.

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In this thesis, the turbulent flow induced by sail masts is simulated using compressible k-w SST detached eddy simulation (DES). The mast is investigated in two different yaw angles at 0 and 90 and the predetermined condition is V = 20 m/s to find the main broadband and tonal noise sources. And then the same cases are compared to simple shape of sail mast without internal cavities. The purpose of this work is to investigate whether the cases generate tonal noise when winds past the sail mast. Another objective is to study aerodynamic parameters around the four cases. The influence of the mast tips is assessed and the Sound Pressure Levels (SPL) that are gotten from pressure fluctuations are shown at the end to find the tonal noise and show the study cases with a cavity inside make much more noise than simplified sail mast. By looking at the peaks in the sound pressure level (SPL) the tonal noise at specific frequencies can be found. The commercial software STAR-CCM+ was used for all three parts pre-processing, running simulations, and post-processing to understand the noise generation and aerodynamic features.
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Yu, Chao. « An acoustic intensity-based method and its aeroacoustic applications ». Diss., Connect to online resource - MSU authorized users, 2008.

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Pignier, Nicolas. « Sound propagation from sustainable ground vehicles : from aeroacoustic sources to urban noise ». Licentiate thesis, KTH, Farkost och flyg, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174182.

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Transportation is the main source of environmental noise in Europe, with an estimated 125 million people affected by excessive noise levels from road traffic, causing a burden of noise related diseases and having a substantial economic impact on society. In order to reduce exposure to high levels of traffic noise, two approaches are the topic of extensive research: preventing sound from propagating from roads and railways using for example noise barriers, and reducing the sources of noise themselves. The second solution, which addresses directly the cause of the problem, requires improved design methods, with a more systematic resort to multi-functional design. Addressing cross-functions simultaneously reduces the number of design iterations and the high cost of prototyping. The work presented in this thesis aims at developing methods that can be used to design quieter vehicle concepts within a multi-functional approach, and is articulated around two main axis of research, aerodynamic sound generation and sound propagation. The first axis aims at performing an aeroacoustic analysis to predict aerodynamic sound sources. A hybrid method is used on the example of a type of submerged air inlet called a NACA duct, where the near-field flow is solved through detached eddy simulation (DES) and where the far-field acoustics is computed using the Ffowcs Williams and Hawkings integral. Results for the flow for various operating conditions are presented and validated against experimental data from the literature, with very good agreement. Far-field acoustic results are shown, exhibiting levels and components that are strongly dependent on the operating conditions. This analysis gives a framework for future aeroacoustic analysis in the project, and sets the path for the development of air inlets with improved aerodynamic and aeroacoustic characteristics. The second axis focuses on the propagation of sound from a given source, moving in an urban environment. An approximate boundary method is presented, which relies on the Kirchhoff approximation applied to the Kirchhoff-Helmholtz integral equation. Using this approximation speeds up the computational time compared to using a regular boundary element method. The resulting expression is extended to account for multiple scattering through consecutive updates of the surface pressures, and for moving sources through the introduction of a retarded time and of a Doppler shift. Validation tests for this method are presented, from simple scatterers to a more realistic configuration, showing good agreement with analytical, experimental and simulated work.
Fordon är den främsta källan till bullerexponering i Europa med uppskattningsvis 125 miljoner människor som är utsatta för höga ljudnivåer från vägtrafik, vilket kan orsaka bullerrelaterade häsloproblem samt har en betydande ekonomisk effekt på samhället. För att minska exponeringen för höga ljudnivåer från fordon, finns det två angreppssätt som båda idag är ämne för omfattande forskning: att förhindra ljudutbredning från vägar och järnvägar (till exempel med hjälp av bullerskydd), samt att minska ljudnivån från olika bullerkällor. Den sistnämnda, som direkt riktar sig till problemets orsak, kräver förbättrade designmetoder med mer systematisk användning av multifunktionell design. Att hantera flera funktioner hos fordonet samtidigt minskar antalet designiterationer och den höga kostnaden för prototyper. Arbetet som presenteras i denna avhandling syftar till att utveckla metoder som kan användas för att utforma tystare fordonskoncept inom ramen för en multifunktionell strategi och fokuserar på två spår i forskningen: aerodynamisk ljudalstring och ljudutbredning från rörliga källor. Det första spåret i forskningen syftar till att utföra en aeroakustisk undersökning för att modellera aerodynamiska ljudkällor. En hybridmetod tillämpas på ett typ av nedsänkt luftintag, kallat NACA-intag, där källområdet i strömningen löses genom detached eddy simulation (DES) och akustiken i fjärrfältet beräknas enligt Ffowcs Williams och Hawkings integral. Resultat för strömningen för olika driftförhållanden presenteras och valideras mot experimentella data från litteraturen, med mycket god överensstämmelse. Resultat för det akustika fjärrfältet visas, vilket uppvisar nivåer och komponenter som är starkt beroende av driftförhållandena. Denna analys ger en ram för kommande analyser av aeroakustik inom projektet och visar vägen för utvecklingen av luftintag med förbättrade aerodynamiska och aeroakustika egenskaper. Det andra spåret i forskningsprojektet är inriktat på ljudets utbredning från en given källa som rör sig i en urban miljö. En approximativ randvärdesmetod presenteras som bygger på Kirchhoff approximation tillämpad på Kirchhoff-Helmholtz integralekvation. Med hjälp av denna approximation minskas beräkningstiden jämfort med vanlig boundary element method (BEM). Modellen utvecklas sedan för att kunna hantera flera reflektioner genom att det akustiska trycket på ytorna uppdateras för varje reflektion samt för att kunna hantera rörliga källor genom att introducera tidsfördröjningar och Dopplerförskjutning. Validering för denna modell presenteras, från enkla spridare till en mer realistisk urban konfiguration, som visar god överensstämmelse med analytiskt, experimentellt och simulerat data.

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Nance, Douglas Vinson. « Finite volume schemes optimized for low numerical dispersion and their aeroacoustic applications ». Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/12110.

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Leitch, Thomas A. « Reduction of Unsteady Rotor-Stator Interaction Using Trailing Edge Blowing ». Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/30527.

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An aeroacoustic investigation was performed to assess the effects of adding mass flow at the trailing edges of four stators upstream of an aircraft engine simulator. By using trailing edge blowing to minimize the shed wakes of the stators, the flow into the rotor was made more uniform. In these experiments a reduced number of stators (four) was used in a 1/14 scale model inlet which was coupled to a 4.1 in (10.4 cm) turbofan engine simulator with 18 rotors and 26 downstream stators. This study is a preliminary step toward a more in depth investigation of using trailing edge blowing to reduce unsteady rotor-stator interaction. Steady-state measurements of the aerodynamic flow field and acoustic far field were made in order to evaluate the aeroacoustic performance at three simulator speeds: 40%, 60%, and 88% of the design speed. The lowest test speed of 40% design speed showed the most dramatic reduction in radiated noise. Noise reductions as large as 8.9 dB in the blade passing tone were recorded at 40% design speed, while a tone reduction of 5.5 dB was recorded at 60% design speed. At 88% design speed a maximum tone reduction of 2.6 dB was recorded. In addition, trailing edge blowing reduced the overall sound pressure level in every case. For both the 40% design speed and the 60% design speed, the fan face distortion was significantly reduced due to the trailing edge blowing. The addition of trailing edge blowing from the four upstream stators did not change the total pressure ratio, and the mass flow added by the blowing was approximately 1%. The results of these experiments clearly demonstrate that blowing from the trailing edges of the stators is effective in reducing unsteady rotor-stator interaction and the subsequent forward radiated noise.
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Livres sur le sujet "Aeroacoustic noise"

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Meyer, Harold D. Aeroacoustic analysis of turbofan noise generation. Cleveland, Ohio : Lewis Reserch Center, 1996.

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G, Migliore Paul, et National Renewable Energy Laboratory (U.S.), dir. Semi-empirical aeroacoustic noise prediction code for wind turbines. Golden, Colo : National Renewable Energy Laboratory, 2003.

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3

S, Hultgren Lennart, et NASA Glenn Research Center, dir. Computing jet screech--a complex aeroacoustic feedback system. [Cleveland, Ohio] : National Aeronautics and Space Administration, Glenn Research Center, 2002.

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S, Hultgren Lennart, et NASA Glenn Research Center, dir. Computing jet screech--a complex aeroacoustic feedback system. [Cleveland, Ohio] : National Aeronautics and Space Administration, Glenn Research Center, 2002.

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Loh, Ching Y. Computing jet screech--a complex aeroacoustic feedback system. [Cleveland, Ohio] : National Aeronautics and Space Administration, Glenn Research Center, 2002.

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W, Elliott Joe, Orie Nettie M, United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch., United States. Army Aviation Systems Command. et Langley Research Center, dir. Rotor performance characteristics from an aeroacoustic helicopter wind-tunnel test program. [Washington, D.C.] : National Aeronautics and Space Administration, Scientific and Technical Information Branch, 1986.

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United States. National Aeronautics and Space Administration., dir. A large hemi-anechoic enclosure for community-compatible aeroacoustic testing of aircraft propulsion systems. [Washington, DC] : National Aeronautics and Space Administration, 1993.

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United States. National Aeronautics and Space Administration., dir. A large hemi-anechoic enclosure for community-compatible aeroacoustic testing of aircraft propulsion systems. [Washington, DC] : National Aeronautics and Space Administration, 1993.

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United States. National Aeronautics and Space Administration., dir. A large hemi-anechoic enclosure for community-compatible aeroacoustic testing of aircraft propulsion systems. [Washington, DC] : National Aeronautics and Space Administration, 1993.

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United States. National Aeronautics and Space Administration., dir. A large hemi-anechoic enclosure for community-compatible aeroacoustic testing of aircraft propulsion systems. [Washington, DC] : National Aeronautics and Space Administration, 1993.

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Chapitres de livres sur le sujet "Aeroacoustic noise"

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Leung, Randolph C. K., Harris K. H. Fan et Garret C. Y. Lam. « A Numerical Methodology for Resolving Aeroacoustic-Structural Response of Flexible Panel ». Dans Flinovia - Flow Induced Noise and Vibration Issues and Aspects, 321–42. Cham : Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-09713-8_15.

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Yang, Yan, et Hongling Sun. « Three-Dimensional Aeroacoustic Numerical Simulation of Flow Induced Noise of Mufflers ». Dans Communications in Computer and Information Science, 276–86. Berlin, Heidelberg : Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-53962-6_24.

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Millo, Federico, Francesco Sapio, Benedetta Peiretti Paradisi, Renzo Arina, Andrea Bianco, Mélissa Férand, Alessio Tarabocchia et Annalisa Reviglio. « Computational Aeroacoustic Analysis of noise mitigation potential of complex exhaust systems ». Dans Proceedings, 501–13. Wiesbaden : Springer Fachmedien Wiesbaden, 2021. http://dx.doi.org/10.1007/978-3-658-33466-6_36.

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Gao, Xu, Zhixiong Pan, Dongqiang Zhao et Jianzhong Chai. « Study on Aeroacoustic Noise Effect on Cockpit of Retractable Aerial Refueling Assembly ». Dans Lecture Notes in Electrical Engineering, 565–75. Singapore : Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-7423-5_56.

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Wang, Fang, Qiuhong Liu et Jinsheng Cai. « Unified Computational Aeroacoustic Integral Methods for Noise Radiation and Scattering with Noncompact Bodies ». Dans Communications in Computer and Information Science, 252–64. Berlin, Heidelberg : Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-53962-6_22.

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Bose, Tarit. « Computational Aeroacoustics ». Dans Aerodynamic Noise, 83–128. New York, NY : Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-5019-1_6.

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Galuba, J., et C. Spehr. « Concept for Measuring Aeroacoustic Noise Transmission in Trains Derived from Experience Gained in Aircraft Testing ». Dans Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 165–72. Berlin, Heidelberg : Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-44832-8_22.

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Wagner, Siegfried, Rainer Bareiß et Gianfranco Guidati. « Introduction to Aeroacoustics ». Dans Wind Turbine Noise, 27–65. Berlin, Heidelberg : Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-88710-9_3.

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He, Yinzhi, Z. Yang et Y. Wang. « Wind noise testing at the full scale aeroacoustic wind tunnel of Shanghai Automotive Wind Tunnel Center ». Dans Proceedings, 1369–78. Wiesbaden : Springer Fachmedien Wiesbaden, 2014. http://dx.doi.org/10.1007/978-3-658-05130-3_97.

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Vepa, Ranjan. « Aeroacoustics and Low Noise Design ». Dans Electric Aircraft Dynamics, 169–206. First edition. | Boca Raton, FL : CRC Press, 2020. : CRC Press, 2020. http://dx.doi.org/10.1201/9780429202315-8.

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Actes de conférences sur le sujet "Aeroacoustic noise"

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Staron, Domenic, Matthias Riegel, Reinhard Blumrich et Andreas Wagner. « Aeroacoustic Vehicle Development Method Considering Realistic Wind Conditions ». Dans Noise and Vibration Conference & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States : SAE International, 2023. http://dx.doi.org/10.4271/2023-01-1123.

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<div class="section abstract"><div class="htmlview paragraph">The aeroacoustic development of vehicles is still mainly carried out in wind tunnels under steady flow conditions, although the real situation is different. However, as discussed in several earlier publications, a vehicle experiences unsteady, turbulent flow on road, which results for example from natural wind, wakes of other vehicles, or obstacles at the roadside in combination with side wind. The resulting temporal variations of the wind noise inside the cabin affect the passengers’ comfort and safety through fatigue. To be able to also consider the unsteady aeroacoustics in the vehicle development process, a comprehensive method has been developed that is presented in full for the first time in this paper. The on-road situation is simulated in a realistic and reproducible manner in the full-scale wind tunnel of the University of Stuttgart by means of an active turbulence generator, developed by FKFS. The turbulence generator allows to dynamically vary the flow angle with frequency components of up to 10 Hz. By comparing the unsteady wind noise for different flow situations and different vehicles, a flow scenario has been derived which leads to representative and meaningful aeroacoustic results. The measured temporal wind noise variations are investigated using modulation analysis, which has been adapted to show only relevant information in a comprehensible way. Finally, a psychoacoustic metric for rating the annoyance of unsteady, as well as steady, wind noise has been developed based on listening studies. The metric describes the subjective perception and allows evaluation and optimization of the aeroacoustic behavior specifically regarding the passengers’ comfort. With this new method all wind noise aspects, steady as well as unsteady, can be determined and taken into account for vehicle development. The evaluation and comparison of vehicles and variants is comprehensive and is focused on the passengers’ comfort.</div></div>
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Perugini, Carlo Alberto, Ugo Riccio, Antonio Torluccio, Rouven Mohr, Reinhard Blumrich et Andreas Wagner. « An Efficient Hybrid Computational Process for Interior Noise Prediction in Aeroacoustic Vehicle Development ». Dans Noise and Vibration Conference & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States : SAE International, 2023. http://dx.doi.org/10.4271/2023-01-1120.

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<div class="section abstract"><div class="htmlview paragraph">Numerical methodologies for aeroacoustic analyses are increasingly crucial for car manufacturers to optimize the effectiveness of vehicle development. In the present work, a hybrid numerical tool based on the combination of a delayed detached-eddy simulation and a finite element model, which relies on the Lighthill’s acoustic analogy and the acoustic perturbation equations, is presented. The computational aeroacoustics is performed by the software OpenFOAM and Actran, concerning respectively the CFD and the FEM. The aeroacoustic behavior of the SUV Lamborghini Urus at a cruising speed of 140 km/h has been investigated. The main aerodynamic noise phenomena occurring in the side mirror region in a frequency range up to 5 kHz are discussed. The numerical simulations have been verified against the measurements performed in the aeroacoustic wind tunnel of the University of Stuttgart, operated by FKFS. The predicted exterior noise propagation into the far field has been validated by comparing the sound pressure level with the experimental data measured by exterior microphones, which were located outside the turbulent region beside the wake of the side mirror. Furthermore, the noise transmission into the cabin through the side window has been modeled. Simulation results have been validated by means of interior microphones installed on the driver seat. Both the exterior and the interior noise predictions show very good correlations with experiments. Lastly, a comprehensive investigation of the most critical aeroacoustic sources has been carried out. The numerical tool has been proven to be in good accordance with the microphone array with respect to the distribution of the sound pressure level in the proximity of the side mirror. Besides, the main vortex structures involved in the generation mechanisms of wind noise have been investigated by a CFD analysis. The entire CAA process has been proven to be accurate and suitable for combined analysis between the generation mechanisms of wind noise and the resulting transfer into the interior cabin to the driver’s ear as well.</div></div>
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Parrang, S., J. Ojeda, S. Khelladi et M. Gabsi. « Aeroacoustic noise prediction for SRM ». Dans 7th IET International Conference on Power Electronics, Machines and Drives (PEMD 2014). Institution of Engineering and Technology, 2014. http://dx.doi.org/10.1049/cp.2014.0389.

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Bao, Weicheng, Xi Chen, Dazhi Sun, Qijun Zhao et Dazgu Sun. « Numerical Analysis of Rotor Aeroacoustic Scattering Characteristics Considering Fuselage Aerodynamic Configuration Parameters ». Dans Vertical Flight Society 78th Annual Forum & Technology Display. The Vertical Flight Society, 2022. http://dx.doi.org/10.4050/f-0078-2022-17429.

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Based on the FW-H equations, the CFD method and the time domain equivalent source method (TDSEM), the rotor aeroacousitc scattering characteristics considering the fuselage aerodynamic configuration parameters are calculated and analyzed. First, a set of CFD/FW-H/TDESM hybrid analysis method for rotor/fuselage aeroacoustic characteristics is developed. The aeroacoustic characteristics of the UH-1H rotor in hover and a point acoustic source nearby a rigid sphere are calculated, and the employed numerical analysis method is validated through comparisons with reference data. Then, the aeroacoustic characteristics of the Bo-105 in hover (main rotor/fuselage) are analyzed, and the scattered noise is discussed in detail. Finally, the aeroacoustic characteristics of the AH-64 helicopter in forward flight is calculated. In addition, parameters, such as the distance between fuselage and rotor, are quantified, and some conclusions are obtained. The fuselage will influence the directivity of rotor noise, and an appropriate fuselage configuration will reduce the rotor noise at the azimuth of 250 degrees (1dB in the present case).
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Tautz, Matthias, Manfred Kaltenbacher et Stefan Becker. « Numerical Aeroacoustic Noise Prediction for Complex HVAC Systems ». Dans 10th International Styrian Noise, Vibration & Harshness Congress : The European Automotive Noise Conference. 400 Commonwealth Drive, Warrendale, PA, United States : SAE International, 2018. http://dx.doi.org/10.4271/2018-01-1515.

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Engelmann, Rafael, Christoph Gabriel, Stefan Schoder et Manfred Kaltenbacher. « A Generic Testbody for Low-Frequency Aeroacoustic Buffeting ». Dans 11th International Styrian Noise, Vibration & Harshness Congress : The European Automotive Noise Conference. 400 Commonwealth Drive, Warrendale, PA, United States : SAE International, 2020. http://dx.doi.org/10.4271/2020-01-1515.

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Bennouna, Saad, Said Naji, Olivier Cheriaux, Solene Moreau, Boureima Ouedraogo et Jean Michel Ville. « Aeroacoustic Prediction Methods of Automotive HVAC Noise ». Dans SAE 2015 Noise and Vibration Conference and Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States : SAE International, 2015. http://dx.doi.org/10.4271/2015-01-2249.

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Zhang, Z., et S. T. Raveendra. « Aeroacoustic Noise Source Identification Using Acoustical Holography ». Dans SAE 2005 Noise and Vibration Conference and Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States : SAE International, 2005. http://dx.doi.org/10.4271/2005-01-2499.

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NORUM, THOMAS. « Supersonic rectangular jet impingement noise experiments ». Dans 12th Aeroacoustic Conference. Reston, Virigina : American Institute of Aeronautics and Astronautics, 1989. http://dx.doi.org/10.2514/6.1989-1138.

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PARRY, A., et D. CRIGHTON. « Prediction of counter-rotation propeller noise ». Dans 12th Aeroacoustic Conference. Reston, Virigina : American Institute of Aeronautics and Astronautics, 1989. http://dx.doi.org/10.2514/6.1989-1141.

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Rapports d'organisations sur le sujet "Aeroacoustic noise"

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Moriarty, P., et P. Migliore. Semi-Empirical Aeroacoustic Noise Prediction Code for Wind Turbines. Office of Scientific and Technical Information (OSTI), décembre 2003. http://dx.doi.org/10.2172/15006098.

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Bortolotti, Pietro, Emmanuel Branlard, Andy Platt, Patrick Moriarty, Carlo Bottasso et Carlo Sucameli. Aeroacoustics Noise Model of OpenFAST. Office of Scientific and Technical Information (OSTI), août 2020. http://dx.doi.org/10.2172/1660130.

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