Wavenumber frequency spectra of turbulence in a lifting wake for broadband noise prediction

1997 ◽  
Author(s):  
William Devenport ◽  
Christian Wenger ◽  
Stewart Glegg ◽  
Joseph Miranda ◽  
William Devenport ◽  
...  
Keyword(s):  
Broadband Noise ◽  
Noise Prediction ◽  
Frequency Spectra

Wave number frequency spectra of a lifting wake for broadband noise prediction

AIAA Journal ◽  
1998 ◽  
Vol 36 ◽  
pp. 881-887
Author(s):  
William J. Devenport ◽  
Christian W. Wenger ◽  
Stewart A. Glegg ◽  
Joseph A. Miranda
Keyword(s):  
Broadband Noise ◽  
Wave Number ◽  
Noise Prediction ◽  
Frequency Spectra ◽  
Number Frequency

Wave Number Frequency Spectra of a Lifting Wake for Broadband Noise Prediction

AIAA Journal ◽  
10.2514/2.462 ◽  
1998 ◽  
Vol 36 (6) ◽  
pp. 881-887 ◽  
Author(s):  
William J. Devenport ◽  
Christian W. Wenger ◽  
Stewart A. L. Glegg ◽  
Joseph A. Miranda
Keyword(s):  
Broadband Noise ◽  
Wave Number ◽  
Noise Prediction ◽  
Frequency Spectra ◽  
Number Frequency

Selection of a leading edge noise prediction method for PNoise

2018 ◽  
pp. 214-223
Author(s):  
AM Faria ◽  
MM Pimenta ◽  
JY Saab Jr. ◽  
S Rodriguez
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Prediction Method ◽  
Leading Edge ◽  
Wind Farms ◽  
Broadband Noise ◽  
Turbulence Energy ◽  
Noise Prediction ◽  
Migration Routes ◽  
Turbulent Inflow

Wind energy expansion is worldwide followed by various limitations, i.e. land availability, the NIMBY (not in my backyard) attitude, interference on birds migration routes and so on. This undeniable expansion is pushing wind farms near populated areas throughout the years, where noise regulation is more stringent. That demands solutions for the wind turbine (WT) industry, in order to produce quieter WT units. Focusing in the subject of airfoil noise prediction, it can help the assessment and design of quieter wind turbine blades. Considering the airfoil noise as a composition of many sound sources, and in light of the fact that the main noise production mechanisms are the airfoil self-noise and the turbulent inflow (TI) noise, this work is concentrated on the latter. TI noise is classified as an interaction noise, produced by the turbulent inflow, incident on the airfoil leading edge (LE). Theoretical and semi-empirical methods for the TI noise prediction are already available, based on Amiet’s broadband noise theory. Analysis of many TI noise prediction methods is provided by this work in the literature review, as well as the turbulence energy spectrum modeling. This is then followed by comparison of the most reliable TI noise methodologies, qualitatively and quantitatively, with the error estimation, compared to the Ffowcs Williams-Hawkings solution for computational aeroacoustics. Basis for integration of airfoil inflow noise prediction into a wind turbine noise prediction code is the final goal of this work.

Advanced open rotor noise prediction

2014 ◽  
Vol 118 (1208) ◽  
pp. 1125-1135 ◽  
Author(s):  
M. J. Kingan
Keyword(s):  
High Speed ◽  
Broadband Noise ◽  
Current Status ◽  
Prediction Methods ◽  
Noise Prediction ◽  
Acoustic Data ◽  
Rotor Noise ◽  
Future Challenges ◽  
Open Rotor ◽  
Development And Validation

Abstract The purpose of this paper is to describe the current status of open rotor noise prediction methods and to highlight future challenges in this area. A number of analytic and numerical methods are described which can be used for predicting ‘isolated’ and ‘installed’ open rotor tonal noise. Broadband noise prediction methods are also described and it is noted that further development and validation of the current models is required. The paper concludes with a discussion of the analytical methods which are used to assess the acoustic data collected during the high-speed wind-tunnel testing of a model scale advanced open rotor rig.

Numerical simulation for fan broadband noise prediction

2011 ◽  
Vol 20 (1) ◽  
pp. 58-63 ◽  
Author(s):  
Takaaki Hase ◽  
Nobuhiko Yamasaki ◽  
Tsutomu Ooishi
Keyword(s):  
Numerical Simulation ◽  
Broadband Noise ◽  
Noise Prediction

scholarly journals On the universal trends in the noise reduction due to wavy leading edges in aerofoil–vortex interaction

2019 ◽  
Vol 871 ◽  
pp. 186-211 ◽  
Author(s):  
Jacob M. Turner ◽  
Jae Wook Kim
Keyword(s):  
Noise Reduction ◽  
High Frequency ◽  
Broadband Noise ◽  
Current Work ◽  
Source Distribution ◽  
Source Analysis ◽  
Frequency Noise ◽  
Frequency Spectra ◽  
Low Frequencies ◽  
Leading Edges

Existing studies suggest that wavy leading edges (WLEs) offer substantial reduction of broadband noise generated by an aerofoil undergoing upstream vortical disturbances. In this context, there are two universal trends in the frequency spectra of the noise reduction which have been observed and reported to date: (i) no significant reduction at low frequencies followed by (ii) a rapid growth of the noise reduction that persists in the medium-to-high frequency range. These trends are known to be insensitive to the aerofoil type and flow condition used. This paper aims to provide comprehensive understandings as to how these universal trends are formed and what the major drivers are. The current work is based on very-high-resolution numerical simulations of a semi-infinite flat-plate aerofoil impinged by a prescribed divergence-free vortex in an inviscid base flow at zero incidence angle, continued from recent work by the authors (Turner & Kim, J. Fluid Mech., vol. 811, 2017, pp. 582–611). One of the most significant findings in the current work is that the noise source distribution on the aerofoil surface becomes entirely two-dimensional (highly non-uniform in the spanwise direction as well as streamwise) at high frequencies when the WLE is involved. Also, the sources downstream of the LE make crucial contributions to creating the universal trends across all frequencies. These findings contradict the conventional LE-focused one-dimensional source analysis that has widely been accepted for all frequencies. The current study suggests that the universal trends in the noise-reduction spectra can be properly understood by taking the downstream source contributions into account, in terms of both magnitude and phase variations. After including the downstream sources, it is shown in this paper that the first universal trend is due to the conservation of total (surface integrated) source energy at low frequencies. The surface-integrated source magnitude that decreases faster with the WLE correlates very well with the noise-reduction spectrum at medium frequencies. In the meantime, the high-frequency noise reduction is driven almost entirely by destructive phase interference that increases rapidly and consistently with frequency, explaining the second universal trend.

Turbofan Broadband Noise Prediction Using the Lattice Boltzmann Method

AIAA Journal ◽  
2018 ◽  
Vol 56 (2) ◽  
pp. 609-628 ◽  
Author(s):  
D. Casalino ◽  
A. Hazir ◽  
A. Mann
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Broadband Noise ◽  
Noise Prediction ◽  
Boltzmann Method

scholarly journals CAA broadband noise prediction for aeroacoustic design

2010 ◽  
Vol 6 ◽  
pp. 254-263 ◽  
Author(s):  
R. Ewert ◽  
J. Dierke ◽  
A. Neifeld ◽  
C. Appel ◽  
M. Siefert ◽  
...  
Keyword(s):  
Broadband Noise ◽  
Noise Prediction
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