Journal articles: 'Wind tunnel noise'

1

IIDA, Akiyoshi. "Low Noise Wind Tunnel." Journal of the Society of Mechanical Engineers 108, no. 1042 (2005): 726–27. http://dx.doi.org/10.1299/jsmemag.108.1042_726.

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MAEDA, Tatsuo, and Yoshihiko KONDO. "RTRI's Large-scale Low-noise Wind Tunnel and Wind Tunnel Tests." Quarterly Report of RTRI 42, no. 2 (2001): 65–70. http://dx.doi.org/10.2219/rtriqr.42.65.

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Baumeister, K. J. "Reverberation Effects on Directionality and Response of Stationary Monopole and Dipole Sources in a Wind Tunnel." Journal of Vibration and Acoustics 108, no. 1 (January 1, 1986): 82–90. http://dx.doi.org/10.1115/1.3269307.

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Analytical solutions for the three-dimensional inhomogeneous wave equation with flow in a hardwall rectangular wind tunnel and in the free field are presented for a stationary monopole noise source. Dipole noise sources are calculated by combining two monopoles 180 deg out of phase. Numerical calculations for the modal content, spectral response and directivity for both monopole and dipole sources are presented. In addition, the effect of tunnel alterations, such as the addition of a mounting plate, on the tunnels reverberant response are considered. In the frequency range of practical importance for the turboprop response, important features of the free field directivity can be approximated in a hardwall wind tunnel with flow if the major lobe of the noise source is not directed upstream. However, for an omnidirectional source, such as a monopole, the hardwall wind tunnel and free field response will not be comparable.

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Migliore, Paul, and Stefan Oerlemans. "Wind Tunnel Aeroacoustic Tests of Six Airfoils for Use on Small Wind Turbines*." Journal of Solar Energy Engineering 126, no. 4 (November 1, 2004): 974–85. http://dx.doi.org/10.1115/1.1790535.

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Aeroacoustic tests of seven airfoils were performed in an open jet anechoic wind tunnel. Six of the airfoils are candidates for use on small wind turbines operating at low Reynolds numbers. One airfoil was tested for comparison to benchmark data. Tests were conducted with and without boundary layer tripping. In some cases, a turbulence grid was placed upstream in the test section to investigate inflow turbulence noise. An array of 48 microphones was used to locate noise sources and separate airfoil noise from extraneous tunnel noise. Trailing-edge noise was dominant for all airfoils in clean tunnel flow. With the boundary layer untripped, several airfoils exhibited pure tones that disappeared after proper tripping was applied. In the presence of inflow turbulence, leading-edge noise was dominant for all airfoils.

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Chu, Yijing, Sipei Zhao, Longbiao He, and Feng Niu. "Wind noise suppression in filtered-x least mean squares-based active noise control systems." Journal of the Acoustical Society of America 152, no. 6 (December 2022): 3340–45. http://dx.doi.org/10.1121/10.0016443.

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Wind noise is notorious for its detrimental impacts on audio devices. This letter evaluates the influence of wind noise on the active noise control performance of headphones in a wind tunnel, and the noise reduction is found to decrease with wind speeds. To improve the performance of noise control systems in windy environments, the filtered-x least mean squares algorithm is modified based on the total least squares technique, taking the characteristics of wind noise into account. Computer simulations with real-recorded data demonstrate that the proposed algorithm could improve the noise reduction by approximately 3 dB in windy conditions.

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Li, Zhengnong, and Jianan Li. "Numerical Simulation Study of Aerodynamic Noise in High-Rise Buildings." Applied Sciences 12, no. 19 (September 21, 2022): 9446. http://dx.doi.org/10.3390/app12199446.

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In order to study the aerodynamic noise on the surfaces of high-rise buildings under the action of strong winds, this paper numerically simulated the sound pressure field on the surface of a high-rise building using the large-eddy simulation method combined with the acoustic analog method of FW-H (Ffowcs Williams–Hawkings) equation and obtained the intensity radiation distribution of sound pressure on the surface of the building to further identify the area with the maximum sound pressure intensity of the noise radiation and thus achieve the purpose of locating noise source. The accuracy of the numerical simulation results for aerodynamic noise obtained in this paper was then verified by comparing with the acoustic wind tunnel experimental results. The locations of noise source obtained by numerical simulation and acoustic wind tunnel experiment were in good agreement. The sound pressure intensity pulsation time course was measured by the acoustic wind tunnel experiment, and the noise sound pressure level spectrum of each part of the building surface was obtained by fast Fourier transform (FFT). Furthermore, the spectral characteristics of the noise sound pressure level were analyzed. The results of the sound pressure level spectrum of aerodynamic noise obtained from the numerical simulation were compared with the acoustic wind tunnel experimental results, which were found to be very similar. The analysis of the sound pressure level spectrum of aerodynamic noise on the building surface reveals that the numerical simulation results in the middle- and high-frequency bands of the spectrum are in good agreement with the acoustic wind tunnel experimental results, but there is a difference between those in the low-frequency bands and the acoustic wind tunnel experimental results. The microphone array used to locate the noise source in the acoustic wind tunnel was found to suffer non-eliminable measurement errors, which might be a potential reason for a reasonably slight difference between the experimental and numerical simulation results. The background noise in the low-frequency band of the acoustic wind tunnel sound pressure level spectrum was relatively large, while there was basically no background noise in the numerical simulation. This paper shows that the numerical simulation method combined with large-eddy simulation and acoustic analogy (FW-H) can calculate the aerodynamic noise intensity at various points on the surfaces of high-rise buildings and reasonably predict the location of sound source. In addition, the numerical simulation results are similar to the acoustic wind tunnel experimental results in most frequency bands.

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Li, Hanqin, Bin Fang, and Yongming Zhang. "Research on an Anechoic Wind Tunnel in the Design Phase by Numerical Simulation." Journal of Physics: Conference Series 2173, no. 1 (January 1, 2022): 012006. http://dx.doi.org/10.1088/1742-6596/2173/1/012006.

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Abstract As an important facility for acoustic measurement and research in air medium, anechoic wind tunnel requires high acoustic performance. In this paper, the flow field and acoustic characteristics of anechoic wind tunnel were studied by modeling and simulation. The velocity and pressure distribution of the whole flow field in the wind tunnel are obtained by simulation calculation, and the noise source distribution in the anechoic wind tunnel is studied by the broadband noise source method, which provides a reference for the design, construction and optimization of the anechoic wind tunnel.

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Chen, Jiming, Shenghao Wu, Zhenhua Chen, Jinlei Lyu, and Haitao Pei. "Experimental Research on Noise Reduction for Continuous Transonic Wind Tunnel Loop." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 38, no. 4 (August 2020): 855–61. http://dx.doi.org/10.1051/jnwpu/20203840855.

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The noise level of wind tunnel test section is respected as one of the most important performance specifications to represent the flow field quality, especially for large scale wind tunnel. According to the acoustic experimental research conducted in the 0.6 m continuous transonic wind tunnel of CARDC, main noise sources in the tunnel loop included the compressor, the high-speed diffuser and the test section. To reduce the noise in the test section, it is necessary to prevent the test section from the compressor noise propagated both forward and backward. In 0.6 m wind tunnel loop, acoustic treatments were installed on both the compressor rear cone and the fourth corner to prevent the noise emitted from the compressor from propagating forward. The vanes in the forth corner were filled with glass fibers and covered with perforated panels. And the compressor rear cone was covered with three layers of micro-perforated panels. With acoustic treatment in the tunnel loop and the second throat throttling, the fluctuation pressure coefficient (ΔCp) is lower than 0.8%, which is close to the international advanced level.

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Nachaiyaphum, Kwanjai, and Chonlatee Photong. "An electric power generation improvement for small Savonius wind turbines under low-speed wind." Indonesian Journal of Electrical Engineering and Computer Science 29, no. 2 (February 1, 2023): 618. http://dx.doi.org/10.11591/ijeecs.v29.i2.pp618-625.

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<p>Savonius wind turbines have advantages of self-rotating at low speed wind, high starting torque, and less noise generation. However, they have low electric power generation capacity. This paper presents electric power generation improvement for small Savonius wind turbines when operating at low-speed wind of 1-6 m/s by using optimal Bach-type blades, twist blades and a wind tunnel. The turbine prototypes with the optimum diameter and height of 32 cm were developed with 3 different blade types: conventional semicircular blades, Bach-type blades and twisted 15° blades and a wind tunnel. The experimental results showed that the Savonius wind turbine with Bach-type generated highest electric voltage, which was 19.3% and 7.6% higher compared to conventional blades and twisted 15° blades. The additional wind tunnel could improve electric power generation efficiency by approximately 21.4% compared to the turbines without the tunnels.</p>

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10

IDO, Atsushi. "RTRI's Large-Scale Low-Noise Wind Tunnel." Journal of the Visualization Society of Japan 32, no. 124 (2012): 26–31. http://dx.doi.org/10.3154/jvs.32.124_26.

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TANIDA, Hiroyuki, Kenji MORITA, and Akiyoshi IIDA. "Development of Low-noise Turbulence Wind Tunnel." Proceedings of the Fluids engineering conference 2004 (2004): 228. http://dx.doi.org/10.1299/jsmefed.2004.228.

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YAMAGUCHI, Hikaru, Masakazu TAKEDA, and Yoshiki SUGAWARA. "Self-Making of Small Wind Tunnel with Lowing Noise and Measurements of Aerodynamic Noise by Wind-Tunnel Experiments." Proceedings of Mechanical Engineering Congress, Japan 2020 (2020): J10211. http://dx.doi.org/10.1299/jsmemecj.2020.j10211.

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de Almeida, Odenir, Fernando M. Catalano, and Lourenco Tercio Pereira. "Improvements of a Hard-Wall Closed Test-Section of a Subsonic Wind Tunnel for Aeroacoustic Testing." International Journal of Acoustics and Vibration 26, no. 3 (September 30, 2021): 248–58. http://dx.doi.org/10.20855/ijav.2021.26.31803.

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For achieving accurate aeroacoustic measurements to the aircraft industry, a low-speed wind tunnel, primarily designed for aerodynamic testing, is modified to provide lower background noise environment. Based on data from single microphone at different wind tunnel locations and microphone phased-array measurements inside the test-section, the main noise sources are identified and feasible alternatives are implemented for reducing the background noise such as new acoustically treated corner-vanes and sidewall lining located upstream the drive system. The acoustically transparent concept for the test-section is also investigated showing promising results for further improvements in the wind tunnel. Results are presented for sound pressure levels from single microphone measurements at different locations in the wind tunnel as well as from the beamforming array inside the test-section. Background noise measurements before and after improvements confirm that the ability of performing aeroacoustic tests has significantly increased with noise reduction of 5 dB inside the test-section.

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14

KIKUCHI, Naoshi. "The way of low noise wind tunnel from wind duct." Journal of the Visualization Society of Japan 15, Supplement1 (1995): 305–8. http://dx.doi.org/10.3154/jvs.15.supplement1_305.

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15

Ahmed, Razeen F., Yenas Yendrew, and Noor A. Ahmed. "Building a Practical Anechoic Chamber for Aero-Acoustic Measurements." Applied Mechanics and Materials 607 (July 2014): 685–93. http://dx.doi.org/10.4028/www.scientific.net/amm.607.685.

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The design, manufacture and installation of a practical and cost-effective anechoic chamber for aero-acoustic measurements are presented in this paper. The work was undertaken with a view to measure the aerodynamically generated noise of wind turbines under laboratory conditions. The chamber was designed to be used in conjunction with a wind tunnel. Tests were carried out to compare the reduction of noise levels from external sources with and without the chamber. The results obtained suggest a clear reduction of noise levels with different wind speeds, and as expected, resulted with higher reductions at higher wind tunnel speeds.

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16

KUDO, Toshifumi. "2707 Noise Reduction Techniques for the Wind Tunnel." Proceedings of the JSME annual meeting 2008.7 (2008): 95–96. http://dx.doi.org/10.1299/jsmemecjo.2008.7.0_95.

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17

Lee, Y. L. "Effects of body leakage on ventilation and wind noise around a sunroof." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 216, no. 5 (May 1, 2002): 363–71. http://dx.doi.org/10.1243/0954407021529174.

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Some passenger cars with sunroofs open at tilted positions experience reverse flows into cabin rooms and wind noises much louder than in other cars. In this study, flows around an open tilted sunroof are numerically studied with varying body leakage. The effects of body leakage on ventilation and wind noise of a sunroof are examined, in particular. Furthermore, flow visualization, pressure and wind noise measured from the wind tunnel and road tests are presented. The results show that too small a body leakage results in poor ventilation performance and generates high wind noises around a sunroof. It is therefore very important to secure an adequate body leakage from the early design stage to achieve better performance of a sunroof as well as passengers' thermal comfort.

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18

Carr, Daniel, and Patricia Davies. "Perception of non-stationary wind noise in vehicles." Noise Control Engineering Journal 70, no. 5 (September 1, 2022): 416–35. http://dx.doi.org/10.3397/1/377036.

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Predictors of people's responses to noise inside cars are used by car companies to identify and address potential noise problems. Because significant advances have been made in the reduction of engine, powertrain, and tire/road noise, it is now important to pursue reductions in wind or aerodynamic noise. While models of loudness are commonly used to predict people's responses to stationary wind noise, some wind noises are less acceptable than is predicted by the loudness metric. Additional sound characteristics may account for this. Two listening studies were designed to examine the usefulness of including sound quality metrics in addition to loudness and sharpness in models used to predict acceptability for non-stationary wind-noise sounds, particularly noise with the kind of variations that are expected from wind gusts. Test sounds were based on recordings made in cars in a wind tunnel. A simulation method was implemented to generate sounds with controlled gusting features by modifying stationary noise recordings. A gusting metric was designed to predict subjects' acceptability responses based on the strength, modulation rate, and duration of the gusts.

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Carr, Daniel, and Patricia Davies. "Perception of stationary wind noise in vehicles." Noise Control Engineering Journal 69, no. 1 (January 1, 2021): 53–65. http://dx.doi.org/10.3397/1/37695.

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Predictors of people's responses to noise inside cars are used by car companies to identify and address potential noise problems from tests. Because significant improvements have been made in engine, powertrain, and tire/road noise, it is now important to pursue improvements in wind or aerodynamic noise. While models of loudness are commonly used to predict people's responses to stationary wind noise, some wind noises are less acceptable than is predicted by loudness metrics. Additional sound characteristics may account for this. Three listening studies were designed to examine the usefulness of including additional sound quality metrics with loudness in models used to predict acceptability for stationary wind-noise sounds. Test sounds were based on recordings made in cars in a wind tunnel. Signal modification techniques were developed to decorrelate metrics across a set of sounds and to examine how acceptability changes with strengths of particular sound characteristics. Models of acceptability for stationary wind noise are significantly improved when a metric that predicts the sharpness of a sound is included in the model with the loudness metric.

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Noh, Hee-Min. "Wind tunnel test analysis to determine pantograph noise contribution on a high-speed train." Advances in Mechanical Engineering 11, no. 10 (October 2019): 168781401988477. http://dx.doi.org/10.1177/1687814019884778.

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In this study, we investigated the characteristics and the influence of the aero-acoustic noise generated from a pantograph using various experimental approaches in a wind tunnel. First, the noise generated at various flow velocities was measured and analyzed using a full-scale pantograph model. Then, the noise generated from the main position of the pantograph was derived using a microphone array attached to one side of a wind tunnel. The noise contributions of the main components of the pantograph were derived from the noise measurements obtained from a step-by-step disassembly of the full-scale model. In addition, the noise reduction achieved by panhead collectors, which are some of the most important noise sources on a pantograph, was examined by studying the results obtained when varying their geometry. In order to analyze the noise-reduction effect achieved by varying the height of the collector, different types of collectors were fabricated and wind tunnel tests were conducted. Through this study, we have investigated the aero-acoustic noise contribution of the major components of a pantograph, and we have developed effective noise-reduction measures for the panhead collector.

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Bielskus, Juozas, and Egidijus Saulius Juodis. "EDUCATIONAL WIND TUNNEL / MOKOMASIS AERODINAMINIS VAMZDIS." Mokslas - Lietuvos ateitis 5, no. 4 (December 31, 2012): 487–92. http://dx.doi.org/10.3846/mla.2012.78.

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The paper analyzes an educational wind tunnel produced by the Department of Building Energetics (DBE) of Vilnius Gediminas Technical University. The equipment could be used for performing laboratory works and simple research. The article presents the projection of inflow and outlet velocity in the working chamber of DBE wind tunnel and carries out actual noise level measurement. The received data are compared with information on the level of noise generated by the fan considering instructions provided by the manufacturer. In order to assess the reliability of the computer program, simulation applying PHOENICS software has been conducted. The aim of modeling is to simulate a pilot model and to compare the obtained results with those of an analogous test presented in scientific articles. Santrauka Straipsnyje nagrinėjamas Vilniaus Gedimino technikos Pastatų energetikos katedros (PEK) mokomasis aerodinaminis vamzdis, su kuriuo galima atlikti laboratorinius darbus ir nesudėtingus mokslinius tyrimus. Pateikta PEK aerodinaminio vamzdžio darbinės kameros įtekėjimo ir ištekėjimo greičių projekcija, taip pat atliktas faktinis triukšmo lygio matavimas, kuris lyginamas su ventiliatoriaus gamintojų pateiktu triukšmo lygiu. Siekiant įvertinti kompiuterinės programos patikimumą, atliktas kompiuterinis modeliavimas programa PHOENICS. Modeliavimo tikslas – sumodeliuoti bandomąjį modelį, gautus rezultatus palyginti su analogiško bandymo rezultatais, pateiktais moksliniuose straipsniuose.

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Lutz, T., A. Herrig, W. Würz, M. Kamruzzaman, and E. Krämer. "Design and Wind-Tunnel Verification of Low-Noise Airfoils for Wind Turbines." AIAA Journal 45, no. 4 (April 2007): 779–85. http://dx.doi.org/10.2514/1.27658.

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SUGAWARA, Taiki, Takahiro KIWATA, Yoshiki SAITO, Takaaki KONO, and Nobuyoshi KOMATSU. "Wind Tunnel Experiment of Aeroacoustic Noise from the Orthopter-type Wind Turbine." Proceedings of Conference of Hokuriku-Shinetsu Branch 2017.54 (2017): C043. http://dx.doi.org/10.1299/jsmehs.2017.54.c043.

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Kuester, Matthew S., and Edward B. White. "Active Noise Control in a Closed-Circuit Wind Tunnel." AIAA Journal 52, no. 9 (September 2014): 1829–38. http://dx.doi.org/10.2514/1.j052275.

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HAYAMA, Kenji, and Katuya SAITO. "Studies on Aeroacoustics Using Kawasaki Low Noise Wind Tunnel." Journal of the Japan Society for Aeronautical and Space Sciences 43, no. 493 (1995): 114–19. http://dx.doi.org/10.2322/jjsass1969.43.114.

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Lölgen, Thomas. "Wind tunnel noise measurements on full‐scale pantograph models." Journal of the Acoustical Society of America 105, no. 2 (February 1999): 1136. http://dx.doi.org/10.1121/1.425410.

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Fukuyama, Eri, Yuichi Tsukamoto, Taku Honda, Akiyoshi IIDA, and Chisachi Kato. "3730 Development of suction typed low-noise wind tunnel." Proceedings of the JSME annual meeting 2006.7 (2006): 87–88. http://dx.doi.org/10.1299/jsmemecjo.2006.7.0_87.

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He, Yin Zhi, and Zhi Gang Yang. "Analysis of Velocity Characteristics of Automobile Interior and Exterior Aerodynamic Noise." Advanced Materials Research 482-484 (February 2012): 1155–60. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.1155.

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After a short introduction about aerodynamic noise generation mechanisms, frequency and velocity characteristics of interior and exterior aerodynamic noise for a production automobile under different wind speeds are investigated through 1:1 aeroacoustic wind tunnel tests. The results show that: Both for the interior and exterior aerodynamic noise, the frequency characteristics keep almost the same as wind speed goes up. The linear OASPL for the interior aerodynamic noise increases at about 4.5th power of wind speed, for the pseudo noise on the vehicle body surface at 4.1th power, for the exterior noise out-of-flow also at 4.1th power. However, the A-weighted OASPL for the interior aerodynamic noise increases at about 5.2th power of wind speed, for the exterior noise out-of-flow at 6.0th power.

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Aizawa, Kai, Susumu Terakado, Masashi Komada, Hidenori Morita, Richard DeJong, and Steve Sorenson. "Turbulent model validations with CFD/wind tunnel test and application to SEA for wind noise prediction." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 6 (August 1, 2021): 175–86. http://dx.doi.org/10.3397/in-2021-1330.

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Wind noise is becoming to have a higher priority in automotive industry. Several past studies investigated whether SEA can be utilized to predict wind noise by applying a turbulent spectrum model as the input. However, there are many kinds of turbulent models developed and the appropriate model for input to SEA is still unclear. Due to this, this paper focuses on clarifying an appropriate turbulent model for SEA simulation. First, the input turbulent pressure spectrum from five models are validated with wind tunnel tests and CFD. Next, a conventional numerical approach is used to validate models from the aspect of response accuracy. Finally, turbulent models are applied to an SEA model developed for a wind tunnel, and the SEA response is validated with test data. From those input/response validations, an appropriate turbulent model is investigated.

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Wu, Han, Chuntai Zheng, Peng Zhou, Ryu Fattah, Xin Zhang, Guocheng Zhou, and Bao Chen. "The multi-functional rotor aerodynamic and aeroacoustic test platform at HKUST." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 2 (August 1, 2021): 4410–17. http://dx.doi.org/10.3397/in-2021-2695.

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This paper describes the multi-functional rotor noise and aerodynamics test platform at the Hong Kong University of Science and Technology (HKUST). To investigate the noise characteristics of propellers with aerodynamic flows, the test rig is installed in the 2.5×2 (m) low-speed and low-noise wind tunnel in the Aerodynamic and Acoustic Facility (AAF) at HKUST. The wind tunnel can facilitate flow from 0 to 40 m/s. The test rig is assembled in a turntable on the ceiling of the tunnel wall, which enables the testing range of pitch angle can vary from 0° (axial flow) to 90° (parallel flow), with an accuracy of 0.1°. The noise produced by the rotor is measured by a set of wall-mounted surface microphones. Semi-empirical calibration is conducted to quantify the noise reflection by the tunnel walls. A low-noise struct has been designed and manufactured to locate a set of far-field microphones equipped with nosecone, to improve the quality of acoustic measurement inside the flow. In addition, a synchronized system is developed to conduct the phase-locking Particle Image Velocimetry (PIV) measurement on the rotor, to study the flow pattern to better understand the noise generation mechanism.

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Rossignol, K.-S., A. Suryadi, M. Herr, J. Schmidt, and J. Tychsen. "Experimental investigation of porous materials for trailing-edge noise reduction." International Journal of Aeroacoustics 19, no. 6-8 (September 1, 2020): 365–84. http://dx.doi.org/10.1177/1475472x20954421.

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The introduction of quiet short take-off and landing for civil aircraft operations in close proximity to the population poses important technological challenges. One critical aspect is the realization of extreme lift augmentation at low acoustic emissions. The aircraft concept selected to achieve this goal is a high-lift system equipped with an active flow-control non-slotted flap and a droop nose. For this specific configuration, trailing edge noise becomes a dominant noise source. Porous materials as a passive means for trailing-edge noise reduction are selected and characterized. Results of extensive experimental investigations in the acoustic wind tunnel Braunschweig are presented and discussed to point out the potential and limitations of the selected porous devices. Practical issues related to material manufacturing and integration into the wind tunnel model are addressed. The noise reduction potential of passive porous trailing-edge devices is found to strongly depend on both these aspects. Issues related to the characterization of the porous materials properties are described. Although porous materials are found to be successful at reducing trailing-edge noise emissions, the results indicate that there is still a need for more generic investigations to further clarify the parametric dependencies between noise reduction and material properties.

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He, Yin Zhi, Zhi Gang Yang, and Yi Gang Wang. "An Experimental Investigation of Automobile Interior Wind Noise Using a Production Vehicle." Applied Mechanics and Materials 105-107 (September 2011): 1860–66. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.1860.

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Based on the analysis of automobile aerodynamic noise generation mechanisms and the components of interior wind noise, the spectra characteristics and spatial distribution rule of sound level of interior wind noise were investigated at first, then the frequency characteristics and noise level under different wind speeds, different yaw angles in SAWTC full-scale aeroacoustic wind tunnel were studied. The results show that: the interior noise level was nearly symmetric on vehicle left and right side, noise level of outboard ear was normally higher than that of inboard ear. The frequency characteristics under different wind speeds were almost the same, the linear OASPL of interior noise increased at about 4.4th power and A-weighted OASPL at about 5.5th power of wind speed. In addition, the acoustic power increased as yaw angle rose up, and noise level by leeward side was normally higher than that by windward under the same yaw angle.

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Mccombe, A. W., J. A. Binnington, and D. Nash. "Wind Noise and Motorcycle Crash Helmets." Journal of Low Frequency Noise, Vibration and Active Control 13, no. 2 (June 1994): 49–57. http://dx.doi.org/10.1177/026309239401300202.

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An investigation was undertaken into the source and levels of wind noise in motorcycle helmets, and their sound attenuation characteristics. All noise measurements increased in a linear fashion when plotted against log10 speed. Low frequency wind noise displayed a greater rate of increase than vehicle noise and surpassed it and the recommended 8 hour occupational maximum of 90dB(A) at approximately 17m/s (40mph/68kph) to reach levels of 111dB(A) at 44m/s (100mph/170kph). There were no statistical differences in the sound levels for different motorcycles, riding position or helmet fit. There were small but significant differences between helmet types. A wind tunnel analysis indicates a turbulent boundary layer as the sound source. As currently designed, a typical motorcycle crash helmet provides no useful sound attenuation below 2000 Hertz and thus little protection against the damaging effects of wind noise. It is suggested that improvements in helmet attenuation characteristics would go some way to addressing this problem.

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Wagner, Alexander, Erich Schülein, René Petervari, Klaus Hannemann, Syed R. C. Ali, Adriano Cerminara, and Neil D. Sandham. "Combined free-stream disturbance measurements and receptivity studies in hypersonic wind tunnels by means of a slender wedge probe and direct numerical simulation." Journal of Fluid Mechanics 842 (March 13, 2018): 495–531. http://dx.doi.org/10.1017/jfm.2018.132.

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Combined free-stream disturbance measurements and receptivity studies in hypersonic wind tunnels were conducted by means of a slender wedge probe and direct numerical simulation. The study comprises comparative tunnel noise measurements at Mach 3, 6 and 7.4 in two Ludwieg tube facilities and a shock tunnel. Surface pressure fluctuations were measured over a wide range of frequencies and test conditions including harsh test environments not accessible to measurement techniques such as Pitot probes and hot-wire anemometry. A good agreement was found between normalized Pitot pressure fluctuations converted into normalized static pressure fluctuations and the wedge probe readings. Quantitative results of the tunnel noise are provided in frequency ranges relevant for hypersonic boundary-layer transition. Complementary numerical simulations of the leading-edge receptivity to fast and slow acoustic waves were performed for the applied wedge probe at conditions corresponding to the experimental free-stream conditions. The receptivity to fast acoustic waves was found to be characterized by an early amplification of the induced fast mode. For slow acoustic waves an initial decay was found close to the leading edge. At all Mach numbers, and for all considered frequencies, the leading-edge receptivity to fast acoustic waves was found to be higher than the receptivity to slow acoustic waves. Further, the effect of inclination angles of the acoustic wave with respect to the flow direction was investigated. An inclination angle was found to increase the response on the wave-facing surface of the probe and decrease the response on the opposite surface for fast acoustic waves. A frequency-dependent response was found for slow acoustic waves. The combined numerical and experimental approach in the present study confirmed the previous suggestion that the slow acoustic wave is the dominant acoustic mode in noisy hypersonic wind tunnels.

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Rovedatti, Vincent, Jacob Milhorn, Richard DeJong, and Gordon Ebbitt. "Vehicle Wind Noise Measurements in a Wind Tunnel with a Contoured Top Profile." SAE International Journal of Passenger Cars - Mechanical Systems 9, no. 1 (April 5, 2016): 234–37. http://dx.doi.org/10.4271/2016-01-1316.

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IIDA, Akiyoshi, Toshitaka MINBU, Kenji MORITA, and Hiroyuki TANIDA. "Attempt to Visualization of Noise Source of Wuthering Noise in a Wind Tunnel." Journal of the Visualization Society of Japan 29-1, no. 1 (2009): 23. http://dx.doi.org/10.3154/jvs.29.23.

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MARUTA, Yoshiyuki. "115 Aerodynamic Noise Difficult to be Analysed with Low Noise Acoustic Wind-Tunnel." Proceedings of the Symposium on Environmental Engineering 2015.25 (2015): 61–64. http://dx.doi.org/10.1299/jsmeenv.2015.25.61.

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Madadnia, Jafar, Deepak Kala, Dheerej Pillai, and Homa Koosha. "Design, Build and Testing of a Noise-Free Twin Shaft Co-Axial Wind Turbine for UTS Buildings." Advanced Materials Research 452-453 (January 2012): 1089–93. http://dx.doi.org/10.4028/www.scientific.net/amr.452-453.1089.

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Management and control of noise pollution in wind turbines are important to integrate wind turbines in building and urban areas. A scaled model of a horizontal-co-axial wind turbine was designed, built and tested in the wind tunnel of University of Technology Sydney (UTS) and its characteristics and aerodynamic-noise emissions were analyzed. The noise reduction capability of the horizontal-twin-shaft wind turbines was compared with wind turbines with the conical entry nozzle (stator), duct-shroud-envelop and vertical shafts. Air velocity, shaft rpm, electric-power generation, noise frequency and amplitude were measured. It was found that up to 15% reduction in the amplitude (dB) of noise emisit from twin shaft wind turbine compared to the single shaft bench mark turbine. The noise analysis performed as a result of these experiments may be used in the design and selection of a building integrated horizontal axis wind turbine for applications at UTS buildings.

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LONG, Bingxiang, Jiming CHEN, Zhenhua CHEN, Zongzheng LIU, and Daxiong LIAO. "Aero-acoustic performance of a continuous transonic wind-tunnel axial-flow compressor." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 40, no. 4 (August 2022): 829–36. http://dx.doi.org/10.1051/jnwpu/20224040829.

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A three-stage axial-flow compressor was developed for a continuous transonic wind tunnel. The rotor-stator spacing and the ratio of number of rotor blades to number of stator vanes were properly chosen for the purpose of aero-acoustic noise suppression. The aero-acoustic performances of the axial-flow compressor were tested and analyzed. The test results show that the first BPF tonal noise is effectively suppressed even though some of it still exists; the noise amplitude frequency spectrum shows that the abnormal tonal noise, which is different from that related to BPF and its harmonics, exists under a wide range of working conditions and plays a dominant role in determining the sound pressure levels of the inlet and outlet of the axial-flow compressor. The comparison of test results shows that vibration is induced by the periodic non-uniform inlet flow condition and that the rotor blade that has a high aspect ratio is one of the main noise sources responsible for the abnormal tonal noise.

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Yin, Jianping, Berend G. van der Wall, and Stefan Oerlemans. "Acoustic Wind Tunnel Tests on Helicopter Tail Rotor Noise (HeliNOVI)." Journal of the American Helicopter Society 53, no. 3 (2008): 226. http://dx.doi.org/10.4050/jahs.53.226.

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MARUTA, Yoshiyuki. "The Aerodynamic Noise not Made Clear With Acoustic Wind-tunnel." Proceedings of Mechanical Engineering Congress, Japan 2021 (2021): W052–02. http://dx.doi.org/10.1299/jsmemecj.2021.w052-02.

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Vishnyakov, V. A., and A. G. Prozorov. "Excitation of velocity fluctuations and noise in a wind tunnel." Fluid Dynamics 27, no. 4 (1993): 580–85. http://dx.doi.org/10.1007/bf01051337.

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43

Kennedy, J., M. Carley, I. Walker, and N. Holt. "On-road and wind-tunnel measurement of motorcycle helmet noise." Journal of the Acoustical Society of America 134, no. 3 (September 2013): 2004–10. http://dx.doi.org/10.1121/1.4817913.

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Collins, S. W., B. W. Westra, J. C. Lin, G. S. Jones, and C. H. Zeune. "Wind tunnel testing of powered lift, all-wing STOL model." Aeronautical Journal 113, no. 1140 (February 2009): 129–37. http://dx.doi.org/10.1017/s0001924000002840.

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Abstract Short take-off and landing (STOL) systems can offer significant capabilities to warfighters and, for civil operators thriving on maximising efficiencies they can improve airspace use while containing noise within airport environments. In order to provide data for next generation systems, a wind tunnel test of an all-wing cruise efficient, short take-off and landing (CE STOL) configuration was conducted in the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) 14ft by 22ft Subsonic Wind Tunnel. The test’s purpose was to mature the aerodynamic aspects of an integrated powered lift system within an advanced mobility configuration capable of CE STOL. The full-span model made use of steady flap blowing and a lifting centerbody to achieve high lift coefficients. The test occurred during April through June of 2007 and included objectives for advancing the state-of-the-art of powered lift testing through gathering force and moment data, on-body pressure data, and off-body flow field measurements during automatically controlled blowing conditions. Data were obtained for variations in model configuration, angles of attack and sideslip, blowing coefficient, and height above ground. The database produced by this effort is being used to advance design techniques and computational tools for developing systems with integrated powered lift technologies.

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Schilden, Thomas, and Wolfgang Schröder. "Numerical analysis of high speed wind tunnel flow disturbance measurements using stagnation point probes." Journal of Fluid Mechanics 833 (November 3, 2017): 247–73. http://dx.doi.org/10.1017/jfm.2017.674.

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Since supersonic test facilities have tunnel noise that strongly influences boundary layer transition experiments, the determination of tunnel noise is of great significance to properly evaluate and interpret experimental results. The composition of tunnel noise, which consists of acoustic, entropy and vorticity modes, highly influences the boundary layer receptivity. The measurement of the separate modes is a major goal of ongoing research. In this study, the properties of stagnation point probes for a newly developed modal decomposition method for tunnel noise are investigated by direct numerical simulation. Pressure and heat flux responses of a stagnation point probe to various entropy and acoustic mode input functions are analysed to investigate how tunnel noise is perceived by corresponding sensor types. The interaction of the incident mode and the shock wave upstream of the probe is analysed and the resulting wave pattern in the subsonic region between shock wave and probe is evidenced. It is found that pure incident acoustic or entropy modes cause acoustic and entropy waves downstream of the shock wave whose strengths differ depending on the incident mode. The resulting wave pattern downstream of the shock wave is determined by postshock acoustic waves propagating bidirectionally between shock wave and probe. Formulating a model equation linking pressure and heat flux fluctuations to the initially caused postshock acoustic and entropy wave, a criterion for the applicability of stagnation point probes measuring pressure and heat flux fluctuations in the new modal decomposition method can be deduced: to distinguish between the incident mode types based on their pressure and heat flux signal the perception of initially generated entropy waves downstream of the shock wave by the heat flux sensor is crucial. The transfer function between entropy waves and heat flux is shown to have low pass filter characteristics and the cutoff Strouhal number could be estimated by control theory. The analysis of the frequency response to continuous incident waves corroborated this cutoff Strouhal number.

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Jessing, Christoph, Daniel Stoll, Timo Kuthada, and Jochen Wiedemann. "New horizons of vehicle aerodynamics." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 231, no. 9 (June 29, 2017): 1190–202. http://dx.doi.org/10.1177/0954407017703245.

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Vehicle aerodynamics and wind tunnel technology are progressing towards more realistic simulations of the real-world on-road environment. This paper presents an overview of the new systems which were implemented during the recent wind tunnel upgrade at Forschungsinstitut für Kraftfahrwesenund Fahrzeugmotoren Stuttgart as well as comparable computational fluid dynamics simulations. The fully interchangeable road simulation system features an interchangeable five-belt system and three-belt system in the same full-scale automotive wind tunnel. This system offers the efficiency of a five-belt system combined with the more sophisticated ground simulation technique of a wide belt system, which is necessary to assess the aerodynamic properties of sports cars and racing cars. In order to simulate on-road wind conditions, a side-wind generator can be installed to generate a turbulent flow field in the wind tunnel test section. It could be shown that the commonly determined drag coefficient at 0° yaw angle in the smooth flow environment of today’s wind tunnels is not representative of the drag found in real on-road wind conditions. Additionally, the investigations in unsteady side-wind conditions indicate that the commonly used approach to determine the side-wind sensitivity of a vehicle underestimates the forces occurring in turbulent flow conditions. A validated simulation model is presented. The simulation results are in good agreement with the experimental results and can be used as a complementary tool when assessing the unsteady aerodynamic behaviour of a vehicle; this behaviour can be coupled to a vehicle dynamics model for virtual road testing in the Stuttgart full-motion driving simulator. The unsteady-behaviour effects can be evaluated comprehensively, and the results allow a subjective assessment of the unsteady response of the vehicle. Furthermore, the aeroacoustic wind noise in on-road wind conditions is investigated during the development of the vehicle. The side-wind generator reproduces the natural stochastic cross-wind and allows the effect of these wind conditions to be investigated in the aeroacoustic wind tunnel. The results show similar ratings to those in on-road tests when compared with subjective listening tests. In summary, the techniques introduced open up new horizons in the field of vehicle aerodynamics and aeroacoustics, which are a step closer towards real-world conditions in automotive engineering.

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Chrysochoidis-Antsos, Nikolaos, Gerard J. W. van Bussel, Jan Bozelie, Sander M. Mertens, and Ad J. M. van Wijk. "Performance Characteristics of A Micro Wind Turbine Integrated on A Noise Barrier." Energies 14, no. 5 (February 26, 2021): 1288. http://dx.doi.org/10.3390/en14051288.

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Micro wind turbines can be structurally integrated on top of the solid base of noise barriers near highways. A number of performance factors were assessed with holistic experiments in wind tunnel and in the field. The wind turbines underperformed when exposed in yawed flow conditions. The theoretical cosθ theories for yaw misalignment did not always predict power correctly. Inverter losses turned out to be crucial especially in standby mode. Combination of standby losses with yawed flow losses and low wind speed regime may even result in a net power consuming turbine. The micro wind turbine control system for maintaining optimal power production underperformed in the field when comparing tip speed ratios and performance coefficients with the values recorded in the wind tunnel. The turbine was idling between 20%–30% of time as it was assessed for sites with annual average wind speeds of three to five meters per second without any power production. Finally, the field test analysis showed that inadequate yaw response could potentially lead to 18% of the losses, the inverter related losses to 8%, and control related losses to 33%. The totalized loss led to a 48% efficiency drop when compared with the ideal power production measured before the inverter. Micro wind turbine’s performance has room for optimization for application in turbulent wind conditions on top of noise barriers.

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KONO, Takaaki, Daiki HIGASHI, Takahiro KIWATA, Shigeo KIMURA, and Nobuyoshi KOMATSU. "Wind Tunnel Experiment on Aeroacoustic Noise from a Straight-Bladed Vertical-Axis Wind Turbine." TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B 79, no. 808 (2013): 2577–81. http://dx.doi.org/10.1299/kikaib.79.2577.

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OINUMA, Hideshi, Katsumi TAKEDA, Kenichiro NAGAI, and Tatsuya ISHII. "1001 Characteristic of Multipurpose Low Noise Wind Tunnel at NAL for Aeroacoustics Noise Research." Proceedings of the Fluids engineering conference 2001 (2001): 123. http://dx.doi.org/10.1299/jsmefed.2001.123.

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Shi, Lei, Wen Qiang Wang, Cheng Chun Zhang, Jing Wang, and Lu Quan Ren. "The Effect of Bionic V-Ring Surface on the Aerodynamic Noise of a Circular Cylinder." Applied Mechanics and Materials 461 (November 2013): 751–62. http://dx.doi.org/10.4028/www.scientific.net/amm.461.751.

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Inspired by stripe shaped structure of owl wing feathers, V-ring surface was proposed in this paper to reduce the aerodynamic noise of a circular cylinder. The effects of V-ring surface on the aerodynamic and aeroacoustic performance of the cylinder were investigated by wind tunnel and numerical simulation. We tested the fluctuating pressure of the smooth cylinder and the V-ring surface cylinder by pulsating pressure sensor in FD-09 wind tunnel of China Academy of Aerospace Aerodynamics（CAAA）. At a wind speed of 42m/s, the Reynolds number is 1.62×105based on the cylinder diameter D of 58mm. The test results showed that the overall fluctuating pressure on the measurement points of the V-ring surface cylinder was significantly decreased compared with the smooth cylinder. The mechanisms of aerodynamic noise control of circular cylinder by V-ring surface were studied by the Large Eddy Simulation（LES）and the Ffowcs Williams and Hawkings （FW-H） equation. The numerical simulation results showed that the aerodynamic noise of the V-ring surface cylinder was reduced by 4.1dB compared to the smooth cylinder. The sound pressure of V-ring surface cylinder model is reduced when the lift fluctuation becomes lower. The V-ring surface is capable of reducing the frequency of the vortex shedding and controlling the fluctuating lift force induced by unstable vortices acting on the cylinder surface.

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Journal articles on the topic 'Wind tunnel noise'

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