Synthesis of fricative sounds using an aeroacoustic noise generation model

1998 ◽  
Vol 103 (5) ◽  
pp. 2775-2775 ◽  
Author(s):  
Daniel J. Sinder ◽  
Michael H. Krane ◽  
James L. Flanagan
Keyword(s):  
Generation Model ◽  
Noise Generation ◽  
Aeroacoustic Noise

Experiments on the flow and acoustic properties of a moderate-Reynolds-number supersonic jet

1982 ◽  
Vol 116 ◽  
pp. 123-156 ◽  
Author(s):  
T. R. Troutt ◽  
D. K. Mclaughlin
Keyword(s):  
Reynolds Number ◽  
Large Scale ◽  
Near Field ◽  
Acoustic Properties ◽  
Generation Model ◽  
Initial Growth ◽  
Noise Generation ◽  
Mean Flow ◽  
Potential Core ◽  
Moderate Reynolds Number

An experimental investigation of the flow and acoustic properties of a moderate-Reynolds-number (Re = 70000), Mach number M = 2·1, axisymmetric jet has been performed. These measurements extended the experimental studies conducted previously in this laboratory to a higher-Reynolds-number regime where the flow and acoustic processes are considerably more complex. In fact, mean-flow and acoustic properties of this jet were determined to be closely comparable to published properties of high-Reynolds-number jets.The major results of the flow-field measurements demonstrate that the jet shear annulus is unstable over a broad frequency range. The initial growth rates and wavelengths of these instabilities as measured by a hot wire were found to be in reasonable agreement with linear stability theory predictions. Also, in agreement with subsonic-jet results, the potential core of the jet was found to be most responsive to excitation at frequencies near a Strouhal number of S = 0·3. The overall development of organized disturbances around S = 0·2 seems to agree in general with calculations performed using the instability theory originally developed by Morris and Tam.The acoustic near field was characterized in terms of sound-pressure level and directivity for both natural and excited (pure-tone) jets. In addition, propagation direction and azimuthal character of dominant spectral components were also measured. It was determined that the large-scale flow disturbances radiate noise in a directional pattern centred about 30° from the jet axis. The noise from these disturbances appears from simple ray tracing to be generated primarily near the region of the jet where the coherent fluctuations saturate in amplitude and begin to decay. It was also determined that the large-scale components of the near-field sound are made up predominately of axisymmetric (n = 0) and helical (n = ±1) modes. The dominant noise-generation mechanism appears to be a combination of Mach-wave generation and a process associated with the saturation and disintegration of the large-scale instability. Finally, the further development of a noise-generation model of the instability type appears to hold considerable promise.

Separation of Engine Noise introducing Noise Generation Model

2002 ◽  
Vol 2002.40 (0) ◽  
pp. 159-160
Author(s):  
Masato KOMORI ◽  
Masato MIKAMI ◽  
Naoya KOJIMA
Keyword(s):  
Generation Model ◽  
Noise Generation ◽  
Engine Noise

Numerical Analysis of Aeroacoustic Noise for High-Speed Face Milling Cutters in Three Dimensional Unsteady Flow Fields

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Chunhui Ji ◽  
Zhanqiang Liu
Keyword(s):  
High Speed ◽  
Reference Frames ◽  
Acoustic Noise ◽  
Environmental Concern ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Flow Fields ◽  
Face Milling ◽  
Noise Generation ◽  
Aeroacoustic Noise

Aeroacoustic noise produced by high speed face milling cutters is a serious environmental concern. This paper develops a modeling approach to investigate the aeroacoustic noise generation and propagation by the idling face milling cutters. The approach consists of two parts: (1) an aerodynamic model for evaluating the flow fields based on the Navier–Stokes (N–S) equation and (2) an aeroacoustic model for predicting the acoustic noise by using the Ffowcs Williams and Hawkings (FW–H) equation. Both the steady mode with the multiple reference frames (MRF) model and the unsteady mode with the sliding mesh technique by introducing steady flow variables as its initial fields are simulated. The cutter gullet regions and the insert rake face regions are found to be the primary contributors in noise generation through spectral analysis of noise sources. The acoustic noise in face milling is significantly affected by the cutter diameter and the number of cutter teeth. The noise directivity is found in vertical plane, and the irregular tooth spacing can spread the maximum sound power at the rotating frequency to higher frequencies. In addition, experiments are conducted to measure the acoustic noise from two high speed milling cutters. It is found that the experimental results are generally in good agreement with the simulations.

Investigation of aeroacoustic noise generation by simultaneous particle image velocimetry and microphone measurements

2008 ◽  
Vol 45 (6) ◽  
pp. 1073-1085 ◽  
Author(s):  
Arne Henning ◽  
Kristian Kaepernick ◽  
Klaus Ehrenfried ◽  
Lars Koop ◽  
Andreas Dillmann
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Noise Generation ◽  
Aeroacoustic Noise ◽  
Image Velocimetry

Implementation and Development of a Stochastic Turbulence Model Based on RANS Formulation for the Prediction of Aeroacoustic Noise

2005 ◽  
Author(s):  
Phachara Niumsawatt ◽  
Sylvester Abanteriba
Keyword(s):  
Flow Field ◽  
Turbulent Flow ◽  
Isotropic Turbulence ◽  
Sound Propagation ◽  
Stokes Equations ◽  
Low Cost ◽  
Attractive Alternative ◽  
Generation Model ◽  
Aeroacoustic Noise ◽  
Turbulent Flow Field

In the computation of aeroacoustic noise, both the Lighthill analogy and the linearized Euler approaches require the definition of source terms involving instantaneous flow fluctuations, which are generally obtained from either Direct Numerical Simulation (DNS) or Large Eddy Simulation (LES). However, these approaches are not economically viable in terms of computational resources, as they require very fine grids to deliver accurate results. Therefore, the Stochastic Velocity Field generation model (SVFG) has has been applied in this paper. The SVFG model is based on the concept of the Stochastic Noise Generation and Radiation (SNGR) without sound propagation and linearized equations. The SVFG model uses time-averaged quantities from the Reynolds Averaged Navier-Stokes equations (RANS) to generate a synthetic time dependent turbulent flow field. The turbulent fluctuations are modeled using a stochastic description of the three-dimensional turbulent motion with a discrete set of Fourier modes. This synthetic turbulent field represents many of the characteristics of real turbulence. Nevertheless, it still has some imperfections; although it exhibits the expected correlation length and the required ratio of length scales, it does not predict the convective properties of shear flow turbulence, as the approach generates homogenous and isotropic turbulence. These properties are shown in this paper with the test case of an axial-symmetrical subsonic jet. The SVFG model is used to generate the turbulent flow field, which then is used to compare with actual experiment measurement and other prediction methods. The results of the comparison show strengths and weaknesses of the model. Since the SVFG approach is relatively low cost when compared to both LES and DNS, it offers an attractive alternative to derive the turbulent flow field.

215 Numerical simulation of separated-reattaching flow between fan blades and the factor of Aeroacoustic noise generation

2016 ◽  
Vol 2016.65 (0) ◽  
pp. _215-1_-_215-2_
Author(s):  
Shuta MAWATARI ◽  
Yusuke GOTO ◽  
Koji IWANO ◽  
Yasuhiko SAKAI ◽  
Yasumasa ITO ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Noise Generation ◽  
Aeroacoustic Noise

scholarly journals A Study on Separation of Combustion Noise Using a Transient Noise Generation Model

2004 ◽  
Vol 70 (692) ◽  
pp. 1106-1111 ◽  
Author(s):  
Yasuo MIURA ◽  
Masato KOMORI ◽  
Masato MIKAMI ◽  
Naoya KOJIMA
Keyword(s):  
Combustion Noise ◽  
Generation Model ◽  
Noise Generation

Aeroacoustic noise generation due to vortex reconnection

2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Hamid Daryan ◽  
Fazle Hussain ◽  
Jean-Pierre Hickey
Keyword(s):  
Noise Generation ◽  
Aeroacoustic Noise ◽  
Vortex Reconnection
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