Calculation Of Noise Research Articles

Rapid Calculation and Optimization of Vibration and Noise of Permanent-Magnet Synchronous Motors for EVs Based on Equivalent Structural Network

Optimizing electromagnetic performance and vibration noise performance simultaneously is important when designing the drive motor for electric vehicles (EVs). This has not been fully explored, and there are only a few relevant studies. To achieve simultaneous optimization, this paper proposes an equivalent structural network (ESN) of stator assembly to calculate the modal distribution and harmonic response transfer functions. Based on the ESN model, the motor’s electromagnetic vibration noise harmonic response, such as acceleration and equivalent radiated power level (ERPL), can be quickly calculated. The feasibility of the established ESN model is verified by structural-field finite-element method (FEM) and modal hammer tests. Based on the modern optimization algorithm and the ESN model, an improved multi-physics and multi-objective optimization design approach is proposed for an optimized design of a 30 kW interior permanent-magnet synchronous machine (IPMSM). The motor’s maximum output torque and ERPL were selected as optimization objectives, and then the ERPL and acceleration were recalculated using structural-field FEM to validate the accuracy of the optimal design. Finally, vibration acceleration tests were carried out on a manufactured prototype motor to verify the feasibility and validity of the proposed optimization design method.

Revision of a common product noise measurement standard in response to user concerns

Many manufacturers of products and equipment use ISO 3744 to measure and report their sound power levels. (ISO 3744 is nationally adopted as an American standard—ANSI/ASA S12.54.) The products include almost all sources that are primarily stationary such as household appliances, computers, heavy machinery, and construction equipment. The standard is referenced in European regulations and hundreds of machine-specific standards. Many users of ISO 3744 have complained that it was too complicated, complex, and difficult to use. In response to these user concerns, the ISO working group responsible (ISO TC43/SC1/WG28) is revising ISO 3744 to make it simpler to use and less complex. Among the many changes, the draft standard includes the following: removing rarely used conditions and reducing the complexity of background noise calculations. The revision also removes certain aspects and places them into two new standards also under development: (1) qualification of measurement rooms ISO 26102-1 and (2) measurement uncertainty ISO 5114-1. Draft standards are being balloted in member countries of ISO TC43/SC1 (Noise). This paper will describe the provisions in the draft revision of each of these three noise standards and their current status.

Building information modeling (BIM) automation for architectural acoustics, mechanical noise calculation

There are several established procedures and design tools for estimating the background sound levels from heating, ventilation and air-conditioning (HVAC) building systems. Building Information Modeling (BIM) is a process commonly used in architecture, engineering, and construction that uses data to generate digital representations of a building’s physical and functional characteristics. We will demonstrate a BIM-automated design tool which uses a Dynamo script and a Revit model duct layout to estimate HVAC noise levels in buildings. With just a few inputs in the model, the script calculates the sound attenuation of each duct element and receiver room sound correction to estimate the HVAC background sound level in any space or building type. Leveraging existing data through BIM automation can help create efficient, optimized designs and improve coordination between mechanical engineers, architects, and acoustical consultants to meet acoustical design criteria.

Road traffic noise modelling and population exposure estimation using CNOSSOS-EU: Insights from Ireland

In 2009 the European Commission sanctioned the development of a new noise calculation method - CNOSSOS-EU - as part of commitments outlined in the Environmental Noise Directive. CNOSSOS-EU aims to develop consistency and cross-national comparability of noise modelling and population exposure results across the EU. This paper assesses the implementation of the CNOSSOS-EU road traffic model for Ireland with a view to determining its effect on future population exposure statistics relative to previous estimations. In order to do this, CNOSSOS-EU and CRTN-TRL models were compared by way of a roadside measurement experiment and population exposure estimation analysis. Results from the roadside measurement experiment indicated that the CNOSSOS-EU model predicts the real noise situation more accurately compared to CRTN-TRL. This suggests that estimates of population exposure statistics calculated under the CNOSSOS-EU method may more accurately reflect the real noise exposure situation than previously reported estimates of population exposure statistics calculated using the CRTN-TRL method. Furthermore, the results found higher levels of population exposure to road traffic noise levels > 55 dB(A) Lden and > 50 dB(A) Lnight using CNOSSOS-EU relative to CRTN-TRL. This has implications for future population exposure estimations and the associated provision of noise action planning within agglomerations.

Development of prediction models of transportation noise for roundabouts and signalized intersections

Accurate transportation noise prediction models are needed by governments and researchers to predict traffic noise levels originating from roadways. This study aims to develop traffic noise prediction models appropriate for roundabouts and signalized intersections of different sizes. Noise measurements, traffic volumes, and different site characteristics were collected at eight two-lane and three-lane roundabouts and signalized intersections. A set of customized general and type-specific noise prediction models were developed and compared. The models were based on the calculation of road traffic noise (CORTN) method. The results indicated that intersection type-specific models fit the measured data for the different intersection types better than general models for the studied conditions. Using these models is expected to be advantageous in terms of predicting traffic noise at roundabouts and signalized intersections. The proposed models could help governments, policymakers, traffic engineers, and urban planners assess and implement necessary noise management and mitigation strategies.

Calculations of the Flow Noise from a Turbulent Boundary Layer for Acoustic Vector Hydrophones in the Flank Array

Calculations of the Flow Noise from a Turbulent Boundary Layer for Acoustic Vector Hydrophones in the Flank Array

Calculation of Noise at the Output of a Phased Antenna Array in a Randomly Inhomogeneous Waveguide

Calculation of Noise at the Output of a Phased Antenna Array in a Randomly Inhomogeneous Waveguide

An Engineering Method for Calculation of Traffic Noise in a Highway Area with Low-Rise Buildings

An Engineering Method for Calculation of Traffic Noise in a Highway Area with Low-Rise Buildings

Research on Numerical Calculation of Reactor Neutron Noise in Frequency Domain and Time Domain

Research on Numerical Calculation of Reactor Neutron Noise in Frequency Domain and Time Domain

Application of autodynes in advanced systems of atmosphere radar sensing

The results of studies of an autodyne transceiver (AT) for advanced radar sensing systems of the atmosphere are presented. A mathematical model of the APP has been developed, presented in the form of an oscillator with a single-circuit oscillatory system under the influence of a request signal from the radar. The analysis of the dynamics of signal reception in the beat mode, when the frequency of the received signal is outside the synchronization band, as well as in the capture mode, when the frequency of the request signal falls into the synchronization band of the AT. The noise and energy parameters and characteristics of the microwave generators used as an AT are investigated. Calculations of dynamic, noise and energy parameters and characteristics of the AT are performed depending on the choice of the type of conductivity characteristic of the active element and the position of the working point on it, as well as on the conditions of connection of the AT with the load. The experimental studies of the AT were carried out on the example of a serial transistor microwave module of the MRS-3MK radiosonde at a frequency of 1680 MHz. The description of the structural scheme of the AT for an aerological radiosonde operating in the beating mode is given. It is shown that the sensitivity of the AT to the request signal is determined by fluctuations in the amplitude of the microwave module and the bandwidth of the intermediate frequency amplifier. It is established that the sensitivity of the AT is minus 110...120 dB/W, for measuring the inclined range of 250...300 km is enough to have a radar transmitter with a pulse power of 50...100 W, while its average power corresponds to 0.05...0.1 W.

Effects of Blowing Location on Aeroacoustics of the Flow over a Circular Cylinder

This study investigated the effect of blowing on vortex shedding and aerodynamic noise due to flow over a circular cylinder. The flow simulation is performed by the URANS equations using k-ω-SST turbulence model. Calculations of the aerodynamic noise are performed through F-fowcs Williams-Hawkins analogy. The cylinder’s cross-section with a diameter of D=16mm, and the blowing jet is applied through slot windows that are located on the cylinder back surface. In this study, three positions for slot windows are considered. Verification of the numerical results is confirmed by comparing numerical results with the reported experimental ones (Uncontrolled case). The results showed that the optimal blowing position could reduce noise, lift coefficient, and drag coefficient; this result occurs for a slot window located near the cylinder horizontal axis of symmetry. On the other hand, if the blowing slot is located at the cylinder symmetric vertical axis, the aerodynamic noise increases by approximately 4 dB. In this case, the average lift and drag fluctuations are increased by more than 200%. The present study gives a new idea to the reduction of noise of the single body systems.

A Transformational Framework for Analysis of Phase Noise in LC Oscillators

Phase noise has become the single most critical factor to be addressed in the design of modern communication systems. Facing the challenging requirements of 5G cellular communication, our paper describes a new theoretical framework to calculate the phase noise of LC oscillators, relying on easy to implement closed form solutions for phase noise calculations. Using closed form phase noise solutions enables oscillator designers to easily implement multiple phase noise calculation options for a number of oscillator circuits, which would be very difficult to implement with the existing mathematically complex phase noise theories. The analytic methods of our theory rely on modeling all real oscillators as having non-ideal or latent behaviors in addition to their primary nature for generating a carrier wave operating at a single frequency with a single amplitude. It is a cascade of these non-ideal transformation processes that produce non-ideal oscillator outputs containing the phase noise sidebands. Enhanced qualitative and quantitative insights into oscillator phase noise performances are achieved by using this approach. We validate our methods by comparing their results with phase noise simulations carried out for a sample CMOS LC voltage-controlled oscillator in 90 nm RFCMOS process using SpectreRF simulator. The results for the oscillator's output 1/f2 thermal phase noise, 1/f noise upconversion into 1/f3 phase noise and the 1/f3 corner frequency of phase noise spectrum using our theory yields −136 dBc/Hz at 10 MHz offset, −21.3 dBc/Hz at 1 kHz offset and 2.6 MHz respectively. The corresponding values obtained with SpectreRF simulation are −135.9 dBc/Hz, −23.4 dBc/Hz and 2.1 MHz. The carrier frequency is 5.4 GHz with output power of 9.78 dBm.

Comparison of the Aircraft Noise Calculation Programs sonAIR, FLULA2 and AEDT with Noise Measurements of Single Flights

As aircraft noise affects large areas around airports, noise exposure calculations need to be highly accurate. In this study, we compare noise exposure measurements with calculations of several thousand single flights at Zurich and Geneva airports, Switzerland, of three aircraft noise calculation programs: sonAIR, a next-generation aircraft noise calculation program, and the two current best-practice programs FLULA2 and AEDT. For one part of the flights, we had access to flight data recorder (FDR) data, which contain flight configuration information that sonAIR can account for. For the other part, only radar data without flight configuration information were available. Overall, all three programs show good results, with mean differences between calculations and measurements smaller than ±0.5 dB in the close range of the airports. sonAIR performs clearly better than the two best-practice programs if FDR data are available. However, in situations without FDR data (reduced set of input data), sonAIR cannot exploit its full potential and performs similarly well as FLULA2 and AEDT. In conclusion, all three programs are well suited to determine averaged noise metrics resulting from complex scenarios consisting of many flights (e.g., yearly air operations), while sonAIR is additionally capable to highly accurately reproduce single flights in greater detail.

Estimation of Phase Noise Transfer Function

Quantifying frequency converters’ residual phase noise is essential in various applications, including radar systems, high-speed digital communication, or particle accelerators. Multi-input signal source analyzers can perform such measurements out of the box, but the high cost limits their accessibility. Based on an analysis of phase noise transmission theory and the capabilities of popular instrumentation, we propose a technique extending the functionality of single-input devices. The method supplements absolute noise measurements with estimates of the phase noise transfer function (also called the jitter transfer function), allowing the calculation of residual noise. The details of the hardware setup used for the method verification are presented. The injection of single-tone and pseudo-random modulations to the test signal is examined. Optional employment of a spectrum analyzer can reduce the time and number of data needed for characterization. A wideband synthesizer with an integrated voltage-controlled oscillator was investigated using the method. The estimated transfer function matches a white-box model based on synthesizer’s structure and values of loop components. The first results confirm the validity of the proposed technique.

Airborne noise calculation for single-layer partitions with the concentrated parameters method

The article considers an approach to the calculation of sound insulation for building partitions with the method of concentrated parameters at the standard frequency range, which is specified in regulatory documents. The concepts of “reduced” and “concentrated” masses are introduced for objects that are sound conductors. It is noted that the physical model of sound insulation in the three conditionally allocated frequency ranges of the standard spectrum has differences. The calculated equations of sound insulation for three frequency ranges are given. Systems of equations for obtaining the calculation formulas at the first and the second frequency ranges are used. The systems consist of equations for the conservation of the amount of motion and the conservation of kinetic energy. The influence of the damping effect of air and resonant phenomena in the plate on the final value of sound insulation is described. The nature of sound propagation in the third frequency range is considered, in which, unlike the first two sections of the frequency spectrum, where the propagation of flexural waves is mainly recorded in the plate, shear and dilatational vibrations have a predominant influence on the sound insulation level. Examples of graphs for massive partitions obtained by the considered method are given. The accuracy of the proposed method is evaluated in comparison with the normative code’s method and the method based on the theory of self-matching of sound fields. A general algorithm for calculating sound insulation in the entire standard frequency range is presented.

Relationship between temperature and road traffic noise under actual conditions of continuous vehicle flow

This paper focuses on studying the influence of temperature on the sound pressure level of tire-road noise emission using continuous environmental noise measurements. In situ noise measurements were performed next to a primary road under free flowing traffic where tire‐road noise emission dominates, while simultaneously monitoring the air and pavement temperature. The broadband results showed a variation in noise level with temperature, with a ratio of −0.058 ± 0.007 dBA/°C for the pavement temperature and −0.161 ± 0.020 dBA/°C for the air temperature. A 1/3 octave band analysis revealed a decrease in sound level with increasing temperature in the fundamental bands of road traffic noise emission, and similar behaviour and values to that observed in the broadband analysis. The physical media in which temperature is measured appears to be important. Several implications may arise from this work in regard to reference standards for noise evaluation, calculation and measurement.

Noise calculation method of deep groove ball bearing caused by vibration of rolling elements considering raceway waviness

Raceway waviness error is the main reason to cause rolling elements to vibrate along axial direction and emit noise. In this paper, the mechanical analysis on deep groove ball bearing is carried out. With auto-correlation function, random surface waviness of both inner and outer raceways is simulated. A contact model of rolling elements and raceways considering surface waviness is established. Combining with the theory of acoustic equation, a calculation model is established for the noise caused by vibration of rolling elements and inner ring. The results show that with the decrease of machining accuracy, the noise of rolling elements increases due to axial vibration; with the increase of rotation speed, the noise also increases. Besides, the spectrum of radiation noise of inner raceway with different waviness amplitudes is given. The results indicate that the 3-D waviness on raceway surface has an influence on the vibration and the noise emitted by both rolling elements and inner ring, and provide guidance for sound control in deep groove rolling bearing.

Sound mapping and acoustic simulations in the implementation of the northern stretch of the Green Line in Curitiba, Paraná, Brazil

The present study aims to study environmental noise pollution in areas close to the northern stretch of the Green Line, in Curitiba, PR, Brazil, which has a length of approximately 8 km. For this purpose, in situ measurements of sound levels were carried out and noise pollution was evaluated through the calculation of noise maps in addition to acoustic simulations. Measurements were recorded at 16 points following the guidelines of the NBR 10151. Acoustic maps were made for each point using proper acoustic software. The aim was to verify whether measured values were within a margin error of up to 4.6 dB(A) compared to simulated values. After validating the maps and verifying the noise pollution at the selected points, one of the points, which is close to a hospital, was analyzed alone to evaluate different simulation scenarios. The selected scenarios were replacement of common asphalt for one with porous properties; 90% restriction on the quantity of heavy vehicles; reduction of average speed of vehicles from 80 km/h to 60 km/h; 50% restriction on the number of vehicles of all categories; and acoustic situation of the site, including all the measurements proposed in the previous scenarios. All scenarios presented in this work reveal that the measurements adopted were not sufficient to reach 55 dB(A) near sensitive areas such as hospitals. They also show that just one control measure is not enough to lower noise efficiently. A plan with several joint measures is needed to alleviate the problem.

Quantifying image quality in chest computed tomography angiography: Evaluation of different contrast-to-noise ratio measurement methods.

Contrast-to-noise ratio is used to objectively evaluate image quality in chest computed tomography angiography (CTA). Different authors define and measure contrast-to-noise ratio using different methods. To summarize and evaluate the different contrast-to-noise ratio calculation formulas in the current literature. A systematic review of the recent literature for studies using contrast-to-noise ratio was performed. Contrast-to-noise ratio measurement methods reported by the different authors were recorded and reproduced in three patients who underwent chest CTA in our department for exploring variations among the different measurement methods. The search resulted in 109 articles, of which 26 were included. The studies involved 69 different measurements and overall, three different formula patterns. In all three, aorta and pulmonary arteries comprised the objects of interest in the numerator. In the denominator, standard deviation of the attenuation of the object of interest itself or of another background were used to reflect image noise. Some authors averaged the ratio values at different levels to obtain global ratio values. Using the object of interest itself for image noise calculation in the denominator compared to the usage of another background caused the most prominent variances of contrast-to-noise ratio between the two different protocols used for the reproduction of the measurements. We recommend using the standard deviation of the attenuation of a background indicator as image noise rather than the object of interest itself for more reliable and comparative values. Global contrast-to-noise ratios based on averaging the values of different measurement levels should be avoided.

Applications of building information modeling software to HVAC noise prediction

This paper presents a methodology and workflow for utilizing Building Information Modeling (BIM) software to expedite the calculation of duct borne noise according to Chapter 49 of the ASHRAE Handbook – HVAC Applications. Using Dynamo script for Autodesk Revit, relevant building mechanical system parameters are extracted to perform noise calculations with reduced manual input. Resulting predictions for receiver sound pressure levels are compared to other software tools available in the industry. Advantages and limitations of this approach are weighed to assess the utility of Building Information Models in the context of the noise prediction workflow. The results of this effort support the development of more robust duct noise prediction tools that are not only more accurate but also more user-friendly.