Aerodynamic noise reduction pdf 3 ± 0. However, it was in the last years that the major actors put in the focus the noise reduction. with high noise levels, there are other issues with excessive noise, like vibrations in structures, fatigue failures in valves and piping systems etc. Trailing edge noise is considered the dominant component of total noise generation attributed to wind turbines. The flow and sound field distribution around a rotating wind turbine with three blades were investigated. Jan 1, 2016 · A broadband noise source model based on Lighthill's acoustic theory was used to perform numerical simulations of the aerodynamic noise sources for a high-speed train. The results show that the streamline bodies of the head/tail car are the most important sound sources, respectively, accounting for 23. 3 / 103 격자볼츠만기법을 이용한 전동차용 견인전동기 공력소음 저감 설계 김 준 형,1 기 호 철,1 변 성 준,2 노 주 현*1 1 현대로템 응용기술연구팀 엑사 코리아 CFD연구팀 2 DESIGN FOR AERODYNAMIC NOISE REDUCTION OF RAILWAY TRACTION MOTOR USING LBM J. The near-field unsteady flow around a high-speed train was analysed based on a delayed detached-eddy simulation (DDES) using the finite volume method with high-order difference schemes. Its design, as a priority, is constrained by requirements associated Mar 4, 2009 · Request PDF | Aerodynamic Noise Reduction using Porous Materials and their Application to High-speed Pantographs | Aerodynamic noise is a major source of wayside noise generated along high-speed May 20, 2017 · Aerodynamic noise is the predominant component of automobile alternator noise at high speed, which directly affects the noise characteristic and noise control of alternator. Read full-text. The experiments were performed for a flat plate test rig, equipped with different reduction of 1. At a tip speed ratio of 5. Vol. Keywords Air curtain ·Fluidic spoiler ·Planar jet ·Tandem jet ·Aerodynamic noise reduction 1 Introduction Landing gear is mechanically complex, primarily designed to support the load of a landing aircraft. JSV. The primary contributors to aerodynamic drag and noise in the intricate structure of high-speed trains include the bogie, pantograph, and both the head and tail cars. The aerodynamic calculations for the toroidal and benchmark propellers were performed to Jun 1, 2022 · Request PDF | Metasurface zero-impedance matching mechanism for aerodynamic noise reduction | In order to control the low-mid frequency aerodynamic noises, the zero-impedance matching mechanism of Jan 20, 2019 · DOI: 10. Sep 1, 2021 · In order to reduce compressor noise and improve compressor acoustic quality, according to the compressor geometric model and the corresponding boundary conditions provided by the manufacturer, the effects of blade number and blade tip clearance of high-speed (100,500 rpm) centrifugal compressor used for gasoline engine on compressor aerodynamic Mar 1, 2023 · The force, noise, and flow field measurements are performed at diameter-based Reynolds numbers ranging from 3 × 10 4 to 1. Table of contents : Preface Acknowledgements Contents List Aug 25, 2023 · Subsequently, structure design and effectiveness of application of porous media for flow control and aerodynamic noise reduction of blunt body external flow, isolated airfoil and rotating Feb 1, 2019 · This reduction has resulted in aerodynamic noise becoming a dominant noise source in wind turbines which is the center of focus in this paper. Mar 1, 2022 · Road tests were done for the modified side car mirror. aerodynamic noise reduction is independent of porous material rigidity [4]. Jan 1, 2023 · Request PDF | On Jan 1, 2023, Deng Qin and others published Numerical Study on Reduction in Aerodynamic Drag and Noise of High-Speed Pantograph | Find, read and cite all the research you need on May 24, 2024 · Notably, the experimental results indicated a 3. Read full-text a numerical model was established to analyze the aerodynamic noise of the toroidal propeller under normal atmospheric conditions. 7% and 33. Ki,1 S. Early turbojets Jan 29, 2024 · Numerical Study on Reduction in Aerodynamic Drag and Noise of High-Speed Pantograph. 22, No. Comput. 02) dB in the overall slat noise (reducing 12 dB of the dominant tone). <p>In this study, wind tunnel experiments are conducted to investigate and analyze the far-field noise of the flow around polygonal cylinders within a Reynolds number range of 2×10<sup>4</sup>–8×10<sup>4</sup>. This paper Feb 2, 2024 · Thus, the aerodynamic drag for the pantograph and the whole system is reduced by 3. 7% increase in air volume flow rate and a 2. Dec 22, 2020 · Schematic diagram of the experimental setup (side view). Acoustic array measurements in a wind tunnel have demonstrated the potential of plasma actuators for slat aerodynamic noise reduction, allowing a decrease of up to (3. 08. reduction in the level of noise produced by modem aircraft power plants must include provisions for controlling and reducing the fan noise. (2019) also investigated the aerodynamic noise reduction in skewed fans by modifying the leading edge serrations and reported that even for forward-leaning fans with low noise levels, serrated leading edges could further reduce aerodynamic noise. However, there is a tradeoff between reducing fan speed, noise and aerodynamic efficiency. At first, cavity noise which causes major noise between car-sections was simulated with Fluent 6. The noise reduction Jul 15, 2016 · Request PDF | Research on aerodynamic noise source characterization and noise reduction of high-speed trains vehicle | To address the complexity of the composition of the aerodynamic noise sources Jun 6, 2024 · Request PDF | On Jun 6, 2024, Minkai Bai and others published Effect of impeller structure on aerodynamic performance and noise reduction of a small multi-blade centrifugal fan | Find, read and May 14, 2013 · Moreover, the noise occurred in gangway is greater than other noise in the room. Jul 19, 2024 · Unmanned Aerial Vehicles (UAVs), or drones, have transformed numerous industries, yet their noise emissions pose challenges in urban and natural environments. Aerodynamic Noise Aerodynamic noise is a direct result of the conversion of Inside private office the mechanical energy of the flow into acoustic energy as the fluid passes through the valve restriction. This successful mitigation of the trade-off between aerodynamic performance and noise level underscores the effectiveness of our bionic design approach. 3 × 10 5 , covering the sub-critical, critical, and supercritical regimes. The issue of increased aerodynamic drag and noise in high-speed trains due to higher speeds requires immediate attention. 5, the best trade offs for a maximum of 1% decrease in power coefficient were a simultaneous decrease in total sound pressure level and starting time of 4% (2 dBA) and 6% respectively, or a decrease in total sound pressure level and starting time of 1% (0. J. 1. Studies about the aircraft noise began, whether developing empirical models, either searching for methods to decrease it. Fans: Aerodynamic Design - Noise Reduction - Optimization 3658379588, 9783658379582 DOWNLOAD PDF FILE. Examples of source control methods include, blade-vane count The ANR sub-project has efforts in airframe noise reduction, propulsion (including fan and core) noise reduction, acoustic liner technology, and propulsion airframe aeroacoustics for candidate conventional and unconventional aircraft configurations. The main noise source of the motor is due to the mechanical excitation of the stator by the Dec 20, 2024 · Active noise cancellation (ANC), among adaptive methods has the potential to reduce noise by 35. A Wells turbine is composed of a cascade of blades | Find, read and cite all the research you need Oct 22, 2022 · A hybrid method incorporating the simulations of noise sources with delayed detached eddy simulation (DDES) and calculations of far-field noise with the Ffowcs Williams–Hawkings (FW-H) equation is used to study the suppression technique for the aerodynamic noise of a Faiveley CX-PG pantograph. 8 dB in free-inlet axial flow fans. become a long-term commitment to jet-noise research that remains today as jet noise continues to draw noise complaints around airports and restricts expansion of commercial aviation. The most successful way to reduce jet noise is to reduce the velocity of the jet. 4 and 1. H. The force and noise measurement results show that dimple fabric simultaneously reduces noise and drag in the critical regime. Thus, the search for more efficient methods of noise reduction is looking toward the field of bionics. 7 Dec 8, 2010 · To reduce the aerodynamic noise generated by a pantograph, which is one of the dominant noise sources in high speed trains, the authors have proposed a set of noise reduction techniques, namely The aim of this study is the reduction of the noise by changing its inlet and outlet pipe length and shape. In current research on aerodynamic noise, the location Jan 13, 2023 · This textbook combines in a unique concept the design and construction of radial and axial fans with the problem of noise generation as well as its mitigation already in the fan development stage. Al-Sadawi and Tze Pei Chong and Jung‐Hoon Kim}, journal={Journal of Sound and Vibration}, year={2019 Mar 14, 2020 · NPT aerodynamic noise is ubiquitous in vehicle flow field, especially in electric vehicles. Tan et al. 0 (computer fluid dynamics program). 5 ms 1, it has been demonstrated that the PA3 (spanwise) plasma actuator is more effective than the PA1 (tangential) and PA2 (downward) plasma actuators in terms of the balance between aerodynamic noise reduction and level of input AC voltage. Jun 14, 2022 · A set of acoustic optimization design methods is established by combining the flow field deterioration theory and the acoustic analogy theory, and applied to the acoustic optimization design of high-speed train snow-plough. The results show that the corrugated pipe is preferable for noise reduction. Schematic for Trap Oct 18, 2020 · Request PDF | Air Curtain Flow Control for Aerodynamic Noise Reduction | In this paper, dual-jet planar air curtains are demonstrated to be able to successfully remove aerodynamic noise radiated J. The characteristics of the Power Spectral Density (PSD) and the Overall Nov 30, 2024 · Request PDF | Numerical Analysis of the Duct Effects on Aerodynamic Noise Reduction for electric Propulsion Fan | The duct helps to minimize the environmental impact on the internal components of effectively suppress the aerodynamic noise. To reduce aerodynamic noise generated by a pantograph, which is one of the dominant noise sources of high-speed trains, the authors proposed some noise reduction techniques, that is, shape-optimization of a panhead, relaxation of aerodynamic interference between Dec 18, 2019 · Request PDF | Slat aerodynamic noise reduction using dielectric barrier discharge plasma actuators | The airplane, during the approach to landing, use high-lift devices to produce more lift at Low-noise design principles were developed and noise reduction analyses were conducted for the main aerodynamic noise sources. Initially the valve manufacturers were Jan 9, 2006 · In addition, preliminary aerodynamic results are shown that support future design goals for significant reductions in airframe noise without compromising safety and performance. 3 dB reduction in noise for the optimized impeller compared to the prototype. The aerodynamic and aero-acoustic mechanism of the rotor-vanes The aircraft noise became the bottleneck for noise reduction and was put into the spotlight [Choudhari and Khorrami, 2003]. By using this suggested modified side view mirror, the risk of annoying noise may be diminished and passenger comfort ability can be increased through driving. 3. Jun 9, 2023 · This study investigates the influence of air blowing on the aerodynamic noise generated by a flat plate with a blunt trailing edge. Both the engine and airframe designs are important in determining the total aircraft noise (see Figure 2). by Deng Qin 1, Xing Du 2, Tian Li 1,*, Jiye Zhang 1 1 State Key Laboratory of Rail Transit Vehicle System, Southwest Jiaotong University, Chengdu, 610031, China 2 School of Electrical Engineering, Southwest Jiaotong University, Chengdu, 610031, China Dec 8, 2010 · Request PDF | Reduction of Aerodynamic Noise from High-speed Pantograph using Porous Materials | Aerodynamic noise is a major source of wayside noise generated by high-speed railway vehicles, and Jan 1, 2024 · These findings confirm the cause of the noise source at the lower part of the leading car inferred in the experimental study by Nagakura (2006) and Sawamura et al. In this study, a numerical model was established to analyze the aerodynamic noise of the toroidal propeller under normal atmospheric conditions. The uniform blowing was applied through evenly spaced holes Reduction of aircraft noise is about optimisation of the whole vehicle, including the way it flies. May 24, 2024 · Then, with the help of the radial basis function (RBF) model and the adaptive simulated annealing (ASA) algorithm, the aerodynamic shape of the fender was optimized to reduce aerodynamic noise. Since fan noise scales with the 4-6th power of the fan tip speed, minimizing the fan tip speed and optimizing the duct geometry are effective methods to reduce fan noise. The rotor noise and loadings were tested in a low-speed anechoic wind tunnel at China Aerodynamics Research and Development Center (CARDC Dec 12, 2019 · The research shows that the aerodynamic noise of the new blade compared to the original blade is significantly reduced at the same rotation speed higher than 1000 rpm, indicating that the blade load noise plays a dominant role in the aerodynamic noise and can be effectively reduced by changing the blade shape along the spanwise, thus reducing Jun 1, 2010 · The noise minimisation was then combined with starting time minimisation to improve low wind speed performance. Topics covered in this Special Issue deal with computational, instrumentation and data analysis of noise and vibrations of fixed wing aircrafts, satellites, spacecrafts, automotives and trains, ranging from aerodynamically generated noise to engine noise, sound absorption, cabin acoustic treatments, duct acoustics and vibroacoustic properties of Nov 28, 2024 · Request PDF | Computational study on aerodynamic noise reduction of high-speed train bogie region using leading edge jet of the bogie cavity | This study employs a numerical approach that combines Oct 22, 2022 · Numerical Study on Aerodynamic Noise Reduction of Pantograph. Based on Lighthill acoustic theory, the aerodynamic noise of an automobile alternator was simulated with three-dimensional, Large eddy simulation (LES) and Ffowcs Williams-Hawkings (FW-H) acoustic model, and the Apr 6, 2023 · Experimental measurements and computational fluid dynamic (CFD) simulations were utilized to examine and compare the aerodynamic performance and noise reduction between twisted and untwisted blades. Considering the influence of angle of attack, two conditions are selected: flow incidence on corner or face. 7% of the total sound noise, low-noise designs, and noise reduction can facilitate the further development of high-speed trains. Dec 12, 2024 · Download full-text PDF. Mar 27, 2019 · PDF | This study focuses on the reduction of aerodynamic noise radiated from a Wells turbine. To reduce noise, it is essential to consider the two main operation orientations of a pantograph, different pantograph fairing structures, different pantograph fairing installations, different choice of which pantograph a low noise technology for landing gear noise reduction. Keywords Acoustic metamaterials ·Appliance noise reduction ·Indirect simulation · Aerodynamic noise 1 Introduction Bladeless fan safety is enhanced as a household appliance Jan 1, 2024 · Lastly, Tong et al. Dec 12, 2019 · Aiming at the problem of excessive propeller noise in a new type of electric aircraft, in order to ensure the propeller aerodynamic characteristics simultaneously, a noise reduction method for May 26, 2024 · The strategic implementation of local blowing (LB) around a circular cylinder within a uniform flow has demonstrated its capacity to effectively suppress aerodynamic noise under specific blowing Sep 1, 2021 · Request PDF | On Sep 1, 2021, Shaoguang Zhang and others published Aerodynamic Optimization and Noise Reduction of a Two-Stage Series Compact Fan | Find, read and cite all the research you need on Dec 9, 2022 · Request PDF | Numerical Modelling of a Wire Mesh for Aerodynamic Noise Reduction | A novel wire mesh consisting of very fine wires and pores is numerically investigated for the purpose of noise Low-noise design principles were developed and noise reduction analyses were conducted for the main aerodynamic noise sources. – Fabricate and deliver a full‐span, 5. From the simulation result, the flow feedback loop phenomena in Jan 1, 2023 · The study indicates a reasonable wave distribution region is benefit to both aerodynamic performance and noise reduction effect. 9 dBA, respectively. As research progresses, collaborative innovation and technology transfer hold potential to Aug 5, 2023 · A noise reduction method for axial flow fans using a short inlet duct is proposed. Other features of this book include introductions to numerical and experimental methods, simulation-based optimization techniques for fan design, and psychoacoustic methods for Case 3 exhibits the highest SPL at the fan’s outlet, with a difference of approximately 5 dB compared to the other cases. Jan 14, 2023 · Easily applicable methods of fan selection, aerodynamic fan design, and fan noise prediction are compiled, including most of the underlying physical principles. 029 Corpus ID: 73568689; Aerodynamic noise reduction by plasma actuators for a flat plate with blunt trailing edge @article{AlSadawi2019AerodynamicNR, title={Aerodynamic noise reduction by plasma actuators for a flat plate with blunt trailing edge}, author={Laith A. 28991/HIJ-2022-03-01-08 Full Text: PDF Jun 21, 2024 · This article presents an optimization process of aerodynamic noise reduction for a novel design called the Toroidal Propeller, which consists of two blades looping joined in a manner where the end Jun 23, 2018 · Request PDF | On Jun 23, 2018, Kun Zhao and others published Aerodynamic noise reduction using dual-jet planar air curtains | Find, read and cite all the research you need on ResearchGate become a long-term commitment to jet-noise research that remains today as jet noise continues to draw noise complaints around airports and restricts expansion of commercial aviation. Byun2 and J. In general industrial operational environment, aerodynamic noise is predominant over mechanical vibration or hydrodynamic / cavitation noise. 71% without affecting the aerodynamic performance of the turbines. Introduction. [17] investigated the use of a wavy leading edge to reduce fan noise at 7000 rpm and showed that this method could lead to fan noise reduction with only minor effects on aerodynamic performance. 103-109, 2017. However, relatively few reports have discussed aerodynamic noise reduction methods for the NPT design. 1016/J. Jan 18, 2010 · Request PDF | Aerodynamic noise reduction by pile fabrics | Pile fabrics are known to be effective at reducing aerodynamic noise. Aerodynamic noise is a major source of wayside noise generated along high-speed rail-way lines, making it important to reduce the phenomenon. Keywords: Aerodynamic Noise; Vehicle Side View Mirror Noise; CFD; Optimization. As such tractable porous urethane was used for the prototype pantograph since it was easier to use. Kim,1 H. A numerical simulation method that A broadband noise source model based on Lighthill’s acoustic theory was used to perform numerical simulations of the aerodynamic noise sources for a high-speed train. The aim is to describe selected, easily applicable methods of aerodynamic design and noise prediction and to demonstrate their physical principles. 82% and 3. Krömer et al. Download full-text PDF. To reduce noise, it is essential to consider the two main operation orientations of a pantograph, different pantograph fairing structures, different pantograph fairing installations, different choice of which pantograph Jan 9, 2025 · 1. May 1, 2013 · Moreover, the noise occurred in gangway is greater than other noise in the room. (2021), and enhance the understanding of the characteristics and generation mechanisms of the bogie aerodynamic noise, which can facilitate the development of noise reduction measures. This study applied this concept of bionics to blade design for horizontal axis wind turbines to reduce aerodynamic noise. 2. They found that the introduction of the spanwise waviness at the front and rear edges of the aerodynamic noise reduction is independent of porous material rigidity [4]. Thereby, the serrated trailing edge of blades is used for noise reduction of aircraft wings, fans and pumps [23, 24]. This noise classification can be further divided into the subcategories of inflow turbulence, trailing edge, and tip noise. Wind tunnel test of prototype pantograph 3. 2018. Therefore, a research for gangway noise reduction was carried out. Doi: 10. It shows that a modified mirror can reduce the sound level of airborne noise. The pattern of noise reduction imposed by the short inlet duct on the axial flow cooling fan under variable Jul 1, 2024 · By adjusting these parameters, the optimal noise reduction effect of 11. However, it is not clear which kind of pile fabric is most Apr 1, 2023 · Request PDF | On Apr 1, 2023, Zonghan Sun and others published Cooling fan aerodynamic noise reduction with short inlet duct and its applicability | Find, read and cite all the research you need Fan noise: Reduction of fan noise radiation to the far field can be followed by five general concepts: (i) reducing the interaction mechanisms between an optimal design of the rotor blades and the stator vanes, or to reduces the velocity deficit in the rotor wakes with the flow control techniques, (ii) reduce the aerodynamic response to an May 12, 2021 · layer separation and turbulent eddies responsible for aerodynamic noise. Considering that China’s Fuxing bullet trains operate at 350 km/h, the inflow velocity of 350 km . To verify its aerodynamic noise reduction effects, Consequently, there is a critical need to reduce noise levels from ventilation fans. H Dec 12, 2024 · Toroidal propellers, a new type of drone propellers capable of significantly reducing noise, offer new possibilities for future low-altitude flying platforms. W3. Introduction Aerodynamic noise is one of the dominant noise sources that occurs in high-speed vehicles. 1 Aerodynamic noise reduction using the proposed methodsmethodsmethods To evaluate the aerodynamic noise of the It is well-known that many species of owl have the unique ability to fly silently, which can be attributed to their distinctive and special feather adaptations. The aerodynamic calculations for the toroidal and benchmark propellers were performed to this aerodynamic noise requirement will avoid vibration problems. 8% scale model for aerodynamic and acoustic testing • NASA Langley conducted aerodynamic (2011) and acoustic (2012 ‐ 2013) tests • Noise assessment process developed to utilize latest data and prediction May 25, 2023 · However, despite the use of aerodynamic acoustics to design low-noise fans or the use of sound absorption, sound insulation, and sound dissipation as the main traditional noise control techniques, they are in a state of technical bottleneck. When the boundary layer Feb 1, 2018 · Request PDF | Review on aerodynamic noise reduction with bionic configuration | Aircraft/engine noise control technology is not only one of the main goals of the current concept of green aviation -aerodynamic noise : noise due to the interaction of the airflow with the impeller and the fixed components of the fan. October 2022; Applied Sciences 12(21):10720; Download full-text PDF Read full-text. Its contribution prevails in most cases -electromagnetic noise : noise of the electric motor that drives the fan. The proportionality of conversion is called acoustical efficiency Feb 2, 2024 · Taking CRH380BL pantograph as the basic prototype, three aerodynamic noise reduction measures of opening, slotting, and airfoil are introduced to build a new pantograph, and their aeroacoustic Jul 1, 2023 · The flight of the owl is silent owing to non-smooth leading edges of the owl’s wings and the curved serration of the feathers. 1, pp. The current review paper focus on advancements in reduction of noise and emphasizing the critical need to mitigate noise pollution from UAV’s. To this end, a new aerody-namic noise reduction method that involves covering the surface of objects with a particu-lar porous material has been developed. The aerodynamic noise of NPT has become the key challenge in clean energy car research. The far-field aerodynamic noise from a Apr 1, 2024 · Request PDF | Aerodynamic noise and its reduction of the marine gas turbine air exhaust system | The aerodynamic noise of pipelines is an important part of the noise of a ship's system. Inspired by the owls, researchers attempted to reduce the aerodynamic noise of aircraft and other structures by learning their noise reduction features from different viewpoints and then using the gained knowledge to develop a number Jan 15, 2023 · The trailing edge of owl wings expands to form a jagged structure in the process of sliding and descending, which makes the aerodynamic noise reduce to a minimum. This study provides a novel structural design for the pantograph cavity region. Jet noise has also become a serious issue around military air bases. It demonstrates the feasibility of acoustic metamaterials to reduce aerodynamic noise. Liu et al. Fluids Eng. 25%, respectively, and the aerodynamic noise is also decreased by 1. Also the losses in noise for different length and shapes have been investigated experimentally. The aerodynamic noise field shows a maximum at 180°, indicating that the fan inlet has the highest noise level, suggesting dipole characteristics in the aerodynamic noise along the test plane. The early work in the area of fan noise reduction developed along two distinct lines: (1) noise source control and (2) noise level reduction. 79 dB can be achieved. C. (2023) investigated Tonal noise reduction at higher mean flow velocities Based on the acoustic and flow results at U ¼ 7. Oct 11, 2016 · Experimental studies using active flow control techniques for trailing edge noise reduction have been carried out. Hand-calculation procedures for predicting aerodynamic noise from propellers, rotors and lift fans useful as first engineering approximations have been assembled from the literature. (2018) studied the application of spanwise waviness in reducing aerodynamic noise of a square bar through experiment and numerical simulation. Dec 12, 2024 · Toroidal propellers, a new type of drone propellers capable of significantly reducing noise, offer new possibilities for future low-altitude flying platforms. Aerodynamic Noise Sources Aerodynamic noise is flow induced noise caused by interaction of flow structures with the blade wall. obiwpv bjidc wqaot gucpuj hzueew ikx ypjxpw jbxuc fwwpise vfa