scholarly journals Effect of measurement-based noise source model of military airplanes on the validity of aircraft noise estimation in Vietnam

2021 ◽  
Vol 42 (1) ◽  
pp. 50-57
Author(s):  
Thanh Loc Bui ◽  
Thu Lan Nguyen ◽  
Makoto Morinaga ◽  
Takashi Morihara ◽  
Yasuhiro Hiraguri
Keyword(s):  
Noise Source ◽  
Source Model ◽  
Aircraft Noise ◽  
Noise Estimation

A simple‐source model of military jet aircraft noise.

2011 ◽  
Vol 129 (4) ◽  
pp. 2442-2442
Author(s):  
Jessica Morgan ◽  
Kent L. Gee ◽  
Tracianne Neilsen ◽  
Alan T. Wall
Keyword(s):  
Source Model ◽  
Aircraft Noise

Wavepacket noise source model for microphone array data analysis of hot supersonic jets

2013 ◽  
Vol 134 (5) ◽  
pp. 4127-4127 ◽  
Author(s):  
Philip Morris ◽  
Robert Dougherty ◽  
Chris Nelson ◽  
Alan Cain ◽  
Kenneth Brentner
Keyword(s):  
Data Analysis ◽  
Noise Source ◽  
Microphone Array ◽  
Source Model ◽  
Supersonic Jets ◽  
Array Data

scholarly journals Anisotropic source modelling for turbulent jet noise prediction

2019 ◽  
Vol 377 (2159) ◽  
pp. 20190075 ◽  
Author(s):  
Xihai Xu ◽  
Xiaodong Li
Keyword(s):  
Large Scale ◽  
Noise Source ◽  
Jet Noise ◽  
Source Model ◽  
Noise Prediction ◽  
Reynolds Stresses ◽  
Acoustic Analogy ◽  
Mean Flow ◽  
Navier Stokes Equation ◽  
Anisotropic Source

An anisotropic component of the jet noise source model for the Reynolds-averaged Navier–Stokes equation-based jet noise prediction method is proposed. The modelling is based on Goldstein's generalized acoustic analogy, and both the fine-scale and large-scale turbulent noise sources are considered. To model the anisotropic characteristics of jet noise source, the Reynolds stress tensor is used in place of the turbulent kinetic energy. The Launder–Reece–Rodi model (LRR), combined with Menter's ω -equation for the length scale, with modified coefficients developed by the present authors, is used to calculate the mean flow velocities and Reynolds stresses accurately. Comparison between predicted results and acoustic data has been carried out to verify the accuracy of the new anisotropic source model. This article is part of the theme issue ‘Frontiers of aeroacoustics research: theory, computation and experiment’.

scholarly journals Investigation and Mitigation of Noise Contributions in a Compact Heterodyne Interferometer

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5788
Author(s):  
Yanqi Zhang ◽  
Adam S. Hines ◽  
Guillermo Valdes ◽  
Felipe Guzman
Keyword(s):  
Noise Source ◽  
Laser Frequency ◽  
Noise Estimation ◽  
Frequency Noise ◽  
Correction Algorithm ◽  
Dynamic Measurements ◽  
Heterodyne Interferometer ◽  
Order Of Magnitude ◽  
Noise Correction ◽  
Laser Interferometers

We present a noise estimation and subtraction algorithm capable of increasing the sensitivity of heterodyne laser interferometers by one order of magnitude. The heterodyne interferometer is specially designed for dynamic measurements of a test mass in the application of sub-Hz inertial sensing. A noise floor of 3.31×10−11m/Hz at 100 mHz is achieved after applying our noise subtraction algorithm to a benchtop prototype interferometer that showed a noise level of 2.76×10−10m/Hz at 100 mHz when tested in vacuum at levels of 3×10−5 Torr. Based on the previous results, we investigated noise estimation and subtraction techniques of non-linear optical pathlength noise, laser frequency noise, and temperature fluctuations in heterodyne laser interferometers. For each noise source, we identified its contribution and removed it from the measurement by linear fitting or a spectral analysis algorithm. The noise correction algorithm we present in this article can be generally applied to heterodyne laser interferometers.

scholarly journals Modeling and Optimization of Impedance Balancing Technique for Common Mode Noise Attenuation in DC-DC Boost Converters

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 480
Author(s):  
Shuaitao Zhang ◽  
Baihua Zhang ◽  
Qiang Lin ◽  
Eiji Takegami ◽  
Masahito Shoyama ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Noise Source ◽  
Effective Means ◽  
Source Model ◽  
Boost Converter ◽  
Modeling Method ◽  
Noise Model ◽  
Resonance Problem ◽  
Common Mode ◽  
Boost Converters

As an effective means of suppressing electromagnetic interference (EMI) noise, the impedance balancing technique has been adopted in the literature. By suppressing the noise source, this technique can theoretically reduce the noise to zero. Nevertheless, its effect is limited in practice and also suffers from noise spikes. Therefore, this paper introduces an accurate frequency modeling method to investigate the attenuation degree of noise source and redesign the impedance selection accordingly in order to improve the noise reduction capability. Based on a conventional boost converter, the common mode (CM) noise model was built by identifying the noise source and propagation paths at first. Then the noise source model was extracted through capturing the switching voltage waveform in time domain and then calculating its Fourier series in frequency domain. After that, the conventional boost converter was modified with the known impedance balancing techniques. This balanced circuit was analyzed with the introduced modeling method, and the equivalent noise source was precisely estimated by combining the noise spectra and impedance information. Furthermore, two optimized schemes with redesigned impedances were proposed to deal with the resonance problem. A hardware circuit was designed and built to experimentally validate the proposed concepts. The experimental results demonstrate the feasibility and effectiveness of the proposed schemes.

Development of Aircraft Noise Source Localization Method with Unmanned Jet Planes.

2004 ◽  
Vol 2004.14 (0) ◽  
pp. 132-135
Author(s):  
Hideshi OINUMA ◽  
Tatsuya ISHII ◽  
Kenichiro NAGAI ◽  
Katsumi TAKEDA
Keyword(s):  
Source Localization ◽  
Noise Source ◽  
Aircraft Noise ◽  
Localization Method

Aircraft Noise Source Identification Using a Microphone Array: Montreal-Trudeau Airport Test Campaign

2013 ◽  
Author(s):  
Robby Lapointe ◽  
Alain Berry ◽  
Cédric Camier ◽  
Jean-Francois Blais ◽  
Mathieu Patenaude-Dufour ◽  
...  
Keyword(s):  
Source Identification ◽  
Noise Source ◽  
Microphone Array ◽  
Aircraft Noise ◽  
Noise Source Identification

scholarly journals A SIMPLE NOISE MODEL WITH MEMORY FOR BIOLOGICAL SYSTEMS

2005 ◽  
Vol 05 (02) ◽  
pp. L243-L250 ◽  
Author(s):  
O. CHICHIGINA ◽  
D. VALENTI ◽  
B. SPAGNOLO
Keyword(s):  
Noise Source ◽  
Pulse Sequence ◽  
Biological Systems ◽  
Source Model ◽  
Noise Model ◽  
Time Behavior ◽  
Correlated Noise ◽  
Infected People ◽  
Random Times ◽  
With Memory

A noise source model, consisting of a pulse sequence at random times with memory, is presented. By varying the memory we can obtain variable randomness of the stochastic process. The delay time between pulses, i.e. the noise memory, produces different kinds of correlated noise ranging from white noise, without delay, to quasi-periodical process, with delay close to the average period of the pulses. The spectral density is calculated. This type of noise could be useful to describe physical and biological systems where some delay is present. In particular it could be useful in population dynamics. A simple dynamical model for epidemiological infection with this noise source is presented. We find that the time behavior of the illness depends on the noise parameters. Specifically the amplitude and the memory of the noise affect the number of infected people.

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