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In-flight measurements of the of coherence length varying with altitude and speed using flight test data.

Haxter, Stefan and Spehr, Carsten (2015) In-flight measurements of the of coherence length varying with altitude and speed using flight test data. Journal of Sound and Vibration, 340 (3), pp. 39-60. Elsevier. DOI: 10.1016/j.jsv.2014.12.005 ISSN 0022-460X

Full text not available from this repository.

Official URL: http://www.sciencedirect.com/science/article/pii/S0022460X14009663

Abstract

Surface pressure fluctuations from several flight attitudes were evaluated in order to find the influence of altitude and speed on the coherence lengths of turbulent structures in the boundary layer. Flight tests were performed using an A320 airplane as a test carrier. Three consecutive window banks in the vicinity of the wing were used to install a pressure transducer array. The array consisted of three aluminum windows equipped with a total of 30 pinhole-mounted pressure transducers [29], [30] and [31]. Assuming a homogenous and ergodic flow the spatial differences between each transducer pairing were considered and the narrow-band coherence was calculated for each pairing. A two-dimensional exponential function was fitted through this coherence, taking the local frequency-dependent flow direction into account [32]. The decay coefficient representative for a remaining coherence of 36 percent was plotted over the frequency and compared with the Efimtsov prediction [33] in Fig. 10. The prediction was found to considerably underestimate the coherence lengths values below 1 kHz. The prediction parameters were adapted to fit the measurements and the resulting curves were compared between different flight altitudes at constant flow velocity and different flow velocities at constant altitude.

Item URL in elib:https://elib.dlr.de/88356/
Document Type:Article
Additional Information:5. Aircraft interior noise, Article 5.1, Page 48-49, Pulished online: 05. Jan. 2015
Title:In-flight measurements of the of coherence length varying with altitude and speed using flight test data.
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Haxter, StefanStefan.Haxter (at) dlr.deUNSPECIFIED
Spehr, CarstenCarsten.Spehr (at) dlr.deUNSPECIFIED
Date:2015
Journal or Publication Title:Journal of Sound and Vibration
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:340
DOI :10.1016/j.jsv.2014.12.005
Page Range:pp. 39-60
Publisher:Elsevier
Series Name:Aeroacoustics research in Europe: The CEAS-ASC report on 2013 highlights
ISSN:0022-460X
Status:Published
Keywords:coherence length, flight altitude, flight speed, flight test
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:fixed-wing aircraft
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Simulation and Validation
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Experimental Methods
Deposited By: Micknaus, Ilka
Deposited On:28 Apr 2015 16:40
Last Modified:10 Jan 2019 15:49

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