Numerical Investigation of Aerodynamic Noise Reduction of Nonpneumatic Tire Using Nonsmooth Riblet Surface

Unlike conventional pneumatic tires, the nonpneumatic tires (NPT) are explosion proof and simple to maintain and provide low rolling resistance. At high vehicle speeds, however, the complex airflow produced by the open flexible-spoke structure of NPT yields high aerodynamic noise, which contributes to sound pollution in the vehicular traffic environment. Inspired by the idea that a nonsmooth riblet structure can affect fluid flow and offer noise reduction, the analyses of the effect of the nonsmooth riblet surface on the aerodynamic noise of an NPT and noise reduction mechanism were presented in this paper. First, computational fluid dynamics (CFD) was used to analyze the surface pressure coefficient characteristics of a smooth flexible-spoke tire rolling at a speed of 80 km/h and subsequently validating the numerical simulation results by comparing them with published test results. Secondly, large eddy simulation (LES) and the Ffowcs Williams–Hawkings (FW-H) method were, respectively, used to determine the transient flow and far-field aerodynamic noise. Then, the mechanism of noise reduction was investigated using a vortex theory. Based on the vortex theory, the positions and strengths of noise sources were determined using the Lamb vector. Finally, according to the fluid boundary layer theory, a nonsmooth riblet surface was arranged on the surface of the spokes, and the influences of the riblet structure parameters, including size, position, and direction, on aerodynamic noise were analyzed. Based on the vortex theory, it was found that the nonsmooth riblet structure can reduce the Lamb vector, suppress the generation of flow vortices, decrease acoustic source strength, and effectively decrease noise up to 5.18 dB using the optimized riblet structure. The study results provide a theoretical basis for the structural design of a new low-noise NPT.

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Research on Aerodynamic Noise Reduction for High-Speed Trains

Shock and Vibration ◽

10.1155/2016/6031893 ◽

2016 ◽

Vol 2016 ◽

pp. 1-21 ◽

Cited By ~ 7

Author(s):

Yadong Zhang ◽

Jiye Zhang ◽

Tian Li ◽

Liang Zhang ◽

Weihua Zhang

Keyword(s):

Noise Reduction ◽

High Speed ◽

Low Noise ◽

Broadband Noise ◽

Full Scale ◽

Noise Model ◽

Aerodynamic Noise ◽

High Speed Train ◽

Detached Eddy Simulation ◽

Noise Sources

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 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. The far-field aerodynamic noise from a high-speed train was predicted using a computational fluid dynamics (CFD)/Ffowcs Williams-Hawkings (FW-H) acoustic analogy. An analysis of noise reduction methods based on the main noise sources was performed. An aerodynamic noise model for a full-scale high-speed train, including three coaches with six bogies, two inter-coach spacings, two windscreen wipers, and two pantographs, was established. Several low-noise design improvements for the high-speed train were identified, based primarily on the main noise sources; these improvements included the choice of the knuckle-downstream or knuckle-upstream pantograph orientation as well as different pantograph fairing structures, pantograph fairing installation positions, pantograph lifting configurations, inter-coach spacings, and bogie skirt boards. Based on the analysis, we designed a low-noise structure for a full-scale high-speed train with an average sound pressure level (SPL) 3.2 dB(A) lower than that of the original train. Thus, the noise reduction design goal was achieved. In addition, the accuracy of the aerodynamic noise calculation method was demonstrated via experimental wind tunnel tests.

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A Design Study of Aerodynamic Noise Reduction In Centrifugal Compressor Part II . Low-noise Optimization Design

Transactions of the Korean Society for Noise and Vibration Engineering ◽

10.5050/ksnvn.2004.14.10.939 ◽

2004 ◽

Vol 14 (10) ◽

pp. 939-944 ◽

Cited By ~ 1

Keyword(s):

Noise Reduction ◽

Centrifugal Compressor ◽

Optimization Design ◽

Low Noise ◽

Aerodynamic Noise ◽

Design Study ◽

Noise Optimization

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Aeroacoustic Source Separation on a Full Scale Nose Landing Gear Featuring Combinations of Low Noise Technologies

ASME 2015 Noise Control and Acoustics Division Conference ◽

10.1115/ncad2015-5912 ◽

2015 ◽

Cited By ~ 3

Author(s):

Eleonora Neri ◽

John Kennedy ◽

Gareth J. Bennett

Keyword(s):

Noise Reduction ◽

Low Noise ◽

Landing Gear ◽

Full Scale ◽

Commercial Aircraft ◽

Noise Sources ◽

Gear Noise ◽

Aircraft Landing ◽

Total Noise ◽

Landing Gear Noise

The reduction of noise generated by aircraft at take-off and approach is crucial in the design of new commercial aircraft. Landing gear noise is significant contribution to the total noise sources during approach. The noise is generated by the interaction between the non-aerodynamic components of the landing gear and the flow, which leads to turbulence generated noise. This research presents results from the European Clean Sky funded ALLEGRA project. The project investigated a full-scale Nose Landing Gear (NLG) model featuring the belly fuselage, bay cavity and hydraulic dressing. A number of low noise treatments were applied to the NLG model including a ramp door spoiler, a wheel axel wind shield, wheel hub caps and perforated fairings. Over 250 far field sensors were deployed in a number of microphone arrays. Since technologies were tested both in isolation and in combination the additive effects of the technologies can be assessed. This study describes the different techniques used to quantify the contribution of each technology to the global noise reduction. The noise reduction technologies will be assessed as a function of frequency range and through beamforming techniques such as source deletion.

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Low Noise FEGV Designed by Numerical Method Based on CFD

Volume 5: Turbo Expo 2004, Parts A and B ◽

10.1115/gt2004-53239 ◽

2004 ◽

Cited By ~ 3

Author(s):

Naoki Tsuchiya ◽

Yoshiya Nakamura ◽

Shinya Goto ◽

Hidekazu Kodama ◽

Osamu Nozaki ◽

...

Keyword(s):

Noise Reduction ◽

Guide Vane ◽

Three Dimensional ◽

Leading Edge ◽

High Amplitude ◽

Aerodynamic Performance ◽

Low Noise ◽

Test Facility ◽

Noise Sources ◽

Fan Noise

This paper describes a low noise FEGV (Fan Exit Guide Vane), which is designed by a fan noise prediction method based on CFD. Fan noise is predicted by a hybrid scheme, which is the combination of three-dimensional CFD and three-dimensional linear theory. Characteristics of noise sources are investigated in some kinds of FEGV shapes. High amplitude areas spread not only along the leading edge but also in the span-wise positions along the mid-chord. It is found that high amplitude areas around the mid-chord make an important role in noise generation, and appropriate aft-ward swept angle and span-wise distribution of leaned angle could reduce the amplitude of the noise sources keeping aerodynamic performance. A fan noise test for fan scale models has been conducted at an anechoic test facility in IHI Mizuho to demonstrate noise reduction and performance of low noise FEGV. Noise reduction can be achieved keeping aerodynamic performance compared to conventional straight FEGV.

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The Application of a Linear Microphone Array in the Quantitative Evaluation of the Blade Trailing-Edge Noise Reduction

Applied Sciences ◽

10.3390/app11020572 ◽

2021 ◽

Vol 11 (2) ◽

pp. 572

Author(s):

Weijie Chen ◽

Luqin Mao ◽

Kangshen Xiang ◽

Fan Tong ◽

Weiyang Qiao

Keyword(s):

Noise Reduction ◽

Quantitative Evaluation ◽

Microphone Array ◽

Experimental Studies ◽

Flow Speed ◽

Aerodynamic Noise ◽

Noise Sources ◽

Trailing Edge ◽

Array Data ◽

Clean Algorithm

This paper concerns the application of a linear microphone array in the quantitative evaluation of blade trailing-edge (TE) noise reduction. The noise radiation from the blades with straight and serrated TEs is measured in an indoor open-jet wind tunnel. The array data are processed using the inverse method based on the Clean algorithm based on spatial source coherence (Clean-SC). In order to obtain correct application and achieve the best effect for the microphone array test, the computing software for array data reduction is firstly developed and assessed by Sarradj’s benchmark case. The assessment results show that the present array data processing method has a good accuracy with an error less than 0.5 dB in a wide frequency range. Then, a linear array with 32 microphones is designed to identify the noise source of a NACA65(12)-10 blade. The performance of the Clean-SC algorithm is compared with the Clean algorithm based on point spread functions (Clean-PSF) method for experimentally identifying the noise sources of the blade. The results show that there is about a 2 dB error when using the Clean-PSF algorithm due to the interference of different aerodynamic noise sources. Experimental studies are conducted to study the blade TE noise reduction using serrated TEs. The TE noise for the blade with and without sawtooth configurations is measured with the flow speeds from 20 m/s to 70 m/s, and the corresponding Reynolds numbers based on the chord are from 200,000 to 700,000. Parametric studies of the sawtooth amplitude and wavelength are conducted to understand the noise reduction law. It is observed that the TE noise reduction is sensitive to both the amplitude and wavelength. The flow speed also affects the noise reduction in the serrated TEs. To obtain the best noise suppression effect, the sawtooth configuration should be carefully designed according to the actual working conditions and airflow parameters.

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Noise Source Localization Using a Compact Phased Array: Studies on a Full Scale Wind Turbine in a Wind Farm

Wind Engineering ◽

10.1260/0309-524x.36.5.589 ◽

2012 ◽

Vol 36 (5) ◽

pp. 589-604 ◽

Cited By ~ 7

Author(s):

Rakesh C. Ramachandran ◽

Ganesh Raman ◽

Robert P. Dougherty

Keyword(s):

Wind Turbine ◽

Wind Farm ◽

Microphone Array ◽

Low Noise ◽

Full Scale ◽

Microphone Arrays ◽

Aerodynamic Noise ◽

Noise Sources ◽

Blade Tip ◽

Primary Focus

Locating the dominant noise sources on a wind turbine is an important problem in designing and developing low noise wind turbines. Previously very large microphone arrays were used to locate these sources. The primary focus of this paper is to show that using a compact and mobile microphone array with advanced beamforming algorithms, the noise sources can be successfully located and quantified. The results from the qualification experiments on the microphone array conducted in laboratory using synthetic noise sources show the differences between the various beamforming algorithms used in this study (both frequency and time domain algorithms). The initial experimental results on a full scale wind turbine reveal that it is indeed possible to locate the noise sources using a compact microphone array by successfully locating the two dominant noise sources on the wind turbine namely, aerodynamic noise near the blade tip and mechanical noise from nacelle.

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ABOUT THE COMMUNITY NOISE PROBLEM OF THE LIGHT PROPELLER AIRCRAFT

Akustika ◽

10.36336/akustika20193466 ◽

2019 ◽

Vol 34 ◽

pp. 66-71

Author(s):

Petr Moshkov ◽

Valery Samokhin ◽

Alexey Yakovlev

Keyword(s):

Power Plant ◽

Noise Reduction ◽

Low Noise ◽

Housing System ◽

Engineering Analysis ◽

Noise Sources ◽

Community Noise ◽

Noise Data ◽

Reduction Methods ◽

Design Power

A light aircraft community noise problem was considered. Basic aircraft noise sources were described. A model was presented to evaluate engine-propeller aircraft power plant noise that may be used while estimating both light aircraft community noise and flight paths providing aircraft inaudibility in the housing system area adjacent to an airfield. An effective engineering analysis agreement of experimental and design power plant noise data has been given. Major light aircraft communication noise reduction methods have been considered. The principal future investigation directions were stated to provide scientific-and-engineering experience in developing present-day low-noise light aircraft has been developed.

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Numerical study on the airfoil self-noise of three owl-based wings with the trailing-edge serrations

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410020988229 ◽

2021 ◽

pp. 095441002098822

Author(s):

Dian Li ◽

Xiaomin Liu ◽

Lei Wang ◽

Fujia Hu ◽

Guang Xi

Keyword(s):

Flow Field ◽

Noise Reduction ◽

Numerical Study ◽

Barn Owl ◽

Aerodynamic Noise ◽

Frequency Noise ◽

Trailing Edge ◽

Reduction Mechanisms ◽

Trailing Edge Serrations ◽

Bionic Airfoil

Previous publications have summarized that three special morphological structures of owl wing could reduce aerodynamic noise under low Reynolds number flows effectively. However, the coupling noise-reduction mechanism of bionic airfoil with trailing-edge serrations is poorly understood. Furthermore, while the bionic airfoil extracted from natural owl wing shows remarkable noise-reduction characteristics, the shape of the owl-based airfoils reconstructed by different researchers has some differences, which leads to diversity in the potential noise-reduction mechanisms. In this article, three kinds of owl-based airfoils with trailing-edge serrations are investigated to reveal the potential noise-reduction mechanisms, and a clean airfoil based on barn owl is utilized as a reference to make a comparison. The instantaneous flow field and sound field around the three-dimensional serrated airfoils are simulated by using incompressible large eddy simulation coupled with the FW-H equation. The results of unsteady flow field show that the flow field of Owl B exhibits stronger and wider-scale turbulent velocity fluctuation than that of other airfoils, which may be the potential reason for the greater noise generation of Owl B. The scale and magnitude of alternating mean convective velocity distribution dominates the noise-reduction effect of trailing-edge serrations. The noise-reduction characteristic of Owl C outperforms that of Barn owl, which suggests that the trailing-edge serrations can suppress vortex shedding noise of flow field effectively. The trailing-edge serrations mainly suppress the low-frequency noise of the airfoil. The trailing-edge serration can suppress turbulent noise by weakening pressure fluctuation.

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