scholarly journals Noise Source Identification in Training Facilities and Gyms

2021 ◽  
Vol 12 (1) ◽  
pp. 54
Author(s):  
Jakub Wróbel ◽  
Damian Pietrusiak
Keyword(s):  
Noise Reduction ◽  
Vibration Isolation ◽  
Room Acoustics ◽  
Noise Sources ◽  
Adaptation Measures ◽  
Acoustic Environment ◽  
Acoustic Adaptation ◽  
Industrial Sites ◽  
Noise Source Identification

This paper deals with noise problems in industrial sites adapted for commercial training venues. The room acoustics of such an object were analyzed in the scope of the reverberation time and potential acoustic adaptation measures are indicated. Identification and classification of noise sources in training facilities and gyms was carried out based on the acoustic measurements. The influence of rubber padding on impact and noise reduction was investigated in the case of chosen noise-intensive exercise activities performed in a previously described acoustic environment. Potential noise reduction measures are proposed in the form of excitation reduction, vibration isolation, and room acoustics adaptation.

Methods of complex reduction of underwater noise of a marine object

2021 ◽  
pp. 28-34
Author(s):  
В.А. Пятакович ◽  
В.Ф. Рычкова ◽  
А.С. Шмаков
Keyword(s):  
Noise Reduction ◽  
Design Process ◽  
Underwater Noise ◽  
Noise Sources ◽  
The Cost

В процессе проектирования к кораблю предъявляется целый ряд требований, удовлетворение которых обеспечивает необходимый уровень его эффективности. Основной целью разработки и обоснования оперативно-тактического задания на проектируемый корабль является определение круга задач, которые должен решать проектируемый корабль, т.е. определение его назначения и выработка на этой основе требований, определяющих как основное, так и дополнительное назначение корабля, и его тактико-технические элементы. В работе представлены проблемные вопросы комплексного применения средств обесшумливания являющиеся достаточно сложными и требующими взаимного согласования эффективности используемых средств исходя из интенсивности источников шума их частотных и фазовых характеристик, оптимизации масс и габаритов, а также стоимости акустической защиты. Представлена классификация методов и средств снижения уровней подводного шума, создаваемого корабельным оборудованием, рассмотрены основные средства снижения подводного шума корабля, обусловленные установкой механизмов и оборудования на виброизолирующую амортизацию и пути снижения модулированного шума корабельных механизмов. During the design process, a number of requirements are imposed on the ship, the satisfaction of which ensures the necessary level of its efficiency. The main purpose of the development and justification of the operational and tactical task for the projected ship is to determine the range of tasks that the projected ship should solve, i.e., determining its purpose and developing on this basis the requirements defining both the main and additional purpose of the ship, and its tactical and technical elements. The paper presents problematic issues of complex application of noise reduction means that are quite complex and require mutual coordination of the effectiveness of the means used based on the intensity of noise sources, their frequency and phase characteristics, optimization of masses and dimensions, as well as the cost of acoustic protection. The classification of methods and means of reducing the levels of underwater noise generated by shipboard equipment is presented, the main means are considered.

Noise Source Identification and Noise Reduction of PDP TV Using Transfer Path Analysis

2010 ◽  
Author(s):  
Hyung-Taek Kwak ◽  
Ji-Hyun Yoon ◽  
In-Hyung Yang ◽  
Jung-Youn Lee ◽  
Jae-Eung Oh
Keyword(s):  
Path Analysis ◽  
Noise Reduction ◽  
Noise Source ◽  
Analysis Method ◽  
Noise Sources ◽  
Transfer Path ◽  
Input Signals ◽  
Noise Source Identification ◽  
Absorbing Materials ◽  
Transfer Path Analysis

The module which is used for the operation of PDP TV consists of three main PCB board, X-board, Y-board, SMPS. Numerous studies on identifying noise sources of PDP TV, and reducing the noise have so far been done through experiments. However, it has been difficult to identify the exact noise sources due to correlations between sources as they are located close to each other. For that reason, Multi-Dimensional Spectral Analysis, MDSA, one of Transfer Path Analysis method, is increasingly required since it enables a quantitative analysis of each input signal’s contribution to the out signal to be carried out by eliminating the correlations of input signals. In this study, Transfer Path Analysis using MDSA is implemented to determine the quantitative noise contribution of each board. And the possibility of noise reduction is confirmed through the experimental method that isolates the most contributing board by adding sound-absorbing materials to it.

Automotive Air Conditioning Compressor Noise Source Identification Method

2015 ◽  
Vol 741 ◽  
pp. 397-400
Author(s):  
Xiao Bo Huang ◽  
Jun Ye ◽  
Shu Sheng Xiong ◽  
Bin Tao Mao ◽  
Ying Hui Wang ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Air Conditioning ◽  
Noise Source ◽  
Air Conditioner ◽  
Noise Sources ◽  
Major Objective ◽  
Identification Methods ◽  
Automotive Air Conditioning ◽  
Automobile Air Conditioner ◽  
Noise Source Identification

With the improvement of requirements for vehicle comfort, people put forward higher requirements on the noise control of automotive air conditioning. As the power source of the automobile air conditioner, the compressor is also the main noise sources, so it is the major objective of vibration damping and noise reduction. In this paper, with analyzing the noise mechanism of compressor, introduces four identification methods of automotive air conditioning compressor noise source, providing theoretical basis for automobile air conditioning damping and noise reduction.

Trailing-edge noise reduction of a wing by a surface modification

2021 ◽  
Vol 263 (3) ◽  
pp. 3194-3201
Author(s):  
Varun Bharadwaj Ananthan ◽  
R.A.D. Akkermans ◽  
Dragan Kozulovic
Keyword(s):  
Noise Reduction ◽  
Stochastic Approach ◽  
Slight Reduction ◽  
Noise Sources ◽  
Trailing Edge ◽  
Sound Sources ◽  
Airframe Noise ◽  
Trailing Edge Noise ◽  
Random Particle ◽  
Noise Production

There is an increased emphasis on reducing airframe noise in the last decades. Airframe noise is sound generated by the interaction of a turbulent flow with the aircraft geometry, and significantly contributes to the overall noise production during the landing phase. One examples of airframe noise is the noise generated at a wing's trailing edge, i.e., trailing-edge noise. In this contribution, we numerically explore the local application of riblets for the purpose of trailing-edge noise reduction. Two configurations are studied: i) a clean NACA0012 wing section as a reference, and ii) the same configuration with riblets installed at the wing's aft part. The numerical investigation follows a hybrid computational aeroacoustics approach, where the time-average flow is studied by means of RANS. Noise sources are generated by means of a stochastic approach called Fast Random Particle Mesh method. The results show a deceleration of the flow behind the riblets. Furthermore, the turbulent kinetic energy indicates increased unsteadiness behind the riblets which is shifted away from the wall due to the presence of the riblets. Lastly, the sound sources are investigated by means of the 3D Lamb-vector, which indicates a slight reduction in magnitude near the trailing edge.

scholarly journals Influence of the use of spring vibration isolators in the construction of track pavement for damping vibrations from the track

2018 ◽  
Vol 2018 (5) ◽  
pp. 1-9
Author(s):  
Ewelina Kwiatkowska ◽  
Wiesław Fiebig
Keyword(s):  
Noise Reduction ◽  
Vibration Isolation ◽  
New Technology ◽  
Track Structure ◽  
Vibration Isolators ◽  
Isolation Systems ◽  
Tuning Frequency ◽  
Mass Spring ◽  
Lower Frequencies

The paper presents tuned track bed vibration isolation systems used for the railway and tramway lines. The presented solution based on mass spring systems and is effective especially at lower frequencies. The tuning frequency of such systems is mostly in the range 5 to 8 Hz. With measures based on spring elements elaborated by GERB company the significant vibration and noise reduction coming from the railways and tramways can be achieved. This new technology in Poland can be used during the track structure modernization as well as in the new projects, in which the track bed vibration isolation is required.

scholarly journals Identification and Removal of Non-acoustic Noise in Towed Array Sonar Using F-Κ Transform for Enhanced Torpedo Detection

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Vibration Isolation ◽  
Acoustic Noise ◽  
Detection System ◽  
Mechanical Vibration ◽  
Low Frequency ◽  
Acoustic Energy ◽  
Noise Sources ◽  
Towed Array ◽  
Spatio Temporal ◽  
Towed Arrays

Low frequency passive towed array sonar is an essential component in a torpedo detection system for surface ships. Compact towed arrays are used for torpedo detection and they will be towed at higher towing speeds compared to conventional towed array sonars used for surveillance. Presence of non-acoustic noise in towed array sensors at higher towing speeds degrades torpedo detection capability at lower frequencies. High wavenumber mechanical vibrations are induced in the array by vortex shedding associated with hydrodynamic flow over the array body and cable scope. These vibrations are known to couple into the hydrophone array as nonacoustic noise sources and can impair acoustic detection performance, particularly in the forward end fire direction. Lengthy mechanical vibration isolation modules can isolate vibration induced noise in towed arrays, but this is not recommended in a towed array which is towed at high speeds as it will increase the drag and system complexity. An algorithm for decomposing acoustic and non-acoustic components of signals received at sensor level using well known frequency-wavenumber transform (F-K transform) is presented here. Frequency-wavenumber diagrams can be used for differentiating between acoustic and non-acoustic signals. An area of V shape is identified within the F-K spectrum where acoustic energy is confined. Energy outside this V will highlight non-acoustic energy. Enhanced simultaneous spatio-temporal and spatio-amplitude detection is possible with this algorithm. Performance of this algorithm is validated through simulation and experimental data.

Proacustica Handbook: noise and vibration control in building installations

2021 ◽  
Vol 263 (1) ◽  
pp. 5057-5062
Author(s):  
Jose Nepomuceno ◽  
Priscila Wunderlich
Keyword(s):  
Vibration Control ◽  
Vibration Isolation ◽  
Control Strategies ◽  
Room Acoustics ◽  
Noise And Vibration ◽  
Technical Content ◽  
Working Groups ◽  
Environmental Acoustics ◽  
The Subject ◽  
The Moment

Proacústica is a nonprofit entity created in 2010 to congregate companies and professionals willing to leverage the development of acoustics in Brazil. Three technical committees (TCs): Environmental Acoustics, Building Acoustics, and Room Acoustics, contribute to the drafting of laws, standards, production of technical content, and integration between different players of the market. By 2021, the Room Acoustics TC incorporated three Working Groups: Special Rooms, Schools and Noise Control and Vibration Control - the last one dedicated to the Proacustica Handbook: Noise and Vibration Control In Building Installations. The purpose of this publication is to describe the step-by-step measures to implement noise and vibration control strategies in buildings. These strategies are aimed at the particularities of the Brazilian market at the moment and also a way to improve how M/E/P equipment manufacturers, installers, designers, and acoustic consultants approach the subject from the design to the construction, Important technical discussions among participants included: the use of sound pressure versus sound power data for equipment; the sound rating for diffusers, VAVs, and other ductwork devices; vibration isolation guidelines, among other topics. This paper presents the Handbook structure, relevant discussions, and recommendations to be published as a final document by the end of 2021.

scholarly journals Innovative passive multifrequency propeller device for noise and vibration reduction in turboprop fuselage

2018 ◽  
Vol 233 ◽  
pp. 00030 ◽  
Author(s):  
Angelo De Fenza ◽  
Maurizio Arena ◽  
Leonardo Lecce
Keyword(s):  
Noise Reduction ◽  
Tonal Noise ◽  
Research Activity ◽  
Noise Sources ◽  
Noise And Vibration ◽  
Aircraft Fuselage ◽  
Research Sector ◽  
Aeronautical Industry ◽  
Flight Regimes ◽  
Passive Noise

One of the main comfort issue affecting the passenger comfort into a turboprop aircraft fuselage is the propeller tonal noise and the related vibrations. It is well known that propeller rotation during flight generates the main noise sources, depending upon its rotational angular velocity, number of blades, power at shaft generating aircraft thrust and blades geometry. Thanks to the progress behind the control systems of the blades rotations, an innovative highly selective DVA has been conceived. The purpose of the research activity has been improving the performances of the standard passive tonal noise control system used for the BPF tuned noise and vibration attenuation in turboprop aircraft. Due to specific commercial need, the use of bi-tuned frequency can lead at a passive noise reduction at two RPM regimes. Generally, the turboprop aircrafts use only two RPM regimes: 100% at take-off, climb and approach, 86% during cruise, climb and descent. An innovative passive bi-tonal device capable to be tuned at two different frequencies in order to optimize the fuselage noise reduction at two different flight regimes (100% and 86%), has been designed and numerically verified. The functional effectiveness of the bi-frequential tuned device has been analysed by finite elements simulations on a linear beam, representative of the turboprop fuselage frame. The outcomes achieved within this activity encourage the advancement of this research sector, as a support to the needs of the turboprop aeronautical industry. According to the long experience gained by the research group, the proposed multifunctional concept can be a valid technology solution ready to be manufactured as well as validated in flight.

Descriptors and Indicators of the Acoustic Environment in Andorra and Escaldes-Engordany

Proceedings ◽  
2019 ◽  
Vol 44 (1) ◽  
pp. 6
Author(s):  
Rosa Alsina-Pagès ◽  
Laura Echevarría-Garuz
Keyword(s):  
Quality Of Life ◽  
Noise Pollution ◽  
The Other ◽  
Physical Parameters ◽  
Noise Sources ◽  
Acoustic Environment ◽  
Audio Recordings ◽  
Using Data ◽  
The City

Noise pollution is one of the growing issues in our cities. Every day the streets are full of vehicles of all kinds and works using noisy machinery; it seems difficult to find a quiet area that away from this acoustic environment. Presently, multiple studies are being carried out in the area of engineering in order to be able to attenuate the causes of this noise pollution, in order to improve citizens’ lives. Nevertheless, are cars the only cause of the noise in the city? Are there other noise sources that may affect the quality of life of the citizens? What defines a city as heavily polluted or not? Maybe it can be assumed that truck noise is annoying and that it contributes to noise pollution, while the sound of birds does not and it is pleasant for people. This paper pretends to analyze the physical parameters that allow us to define if any sound causes annoyance, taking into account its acoustic environment. To do this, a specific case will be analysed; we will study three locations measured in Andorra La Vella and Escaldes-Engordany. The audio recordings will be studied deeply, and compared one to the other using data from two different days and all day schedule. We will finally evaluate the annoyance of each location using parameters such as loudness, sharpness and roughness, and taking into account both day and time, as well as giving details about the several types of sound labelled in each recording.

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