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Experiments on Active Control of Counter-Rotating Open Rotor Interior Noise

Haase, Thomas and Algermissen, Stephan and Unruh, Oliver and Misol, Malte (2014) Experiments on Active Control of Counter-Rotating Open Rotor Interior Noise. Acta acustica united with Acustica (100), pp. 448-457. Hirtzel. DOI: 10.3813/AAA.918725 ISBN Online: 1861-9959 Print: 1610-1928 ISSN 1610-1928

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Abstract

The efficiency of future aircraft has to be increased because of the CO2 restrictions layed down by the European Union. Two key technologies to reach this ambitious goal are a consequent light-weight design of future aircraft and new engine concepts like the Counter-Rotating open rotors (CROR). However, the combination of lightweight materials like carbon-fibre-reinforced plastics (CFRP) with CROR is acoustically demanding because of the very high sound pressures emitted by this type of engine and the poor transmission loss of CFRP structures in the lower frequency range. Therefore, this work conducts a preliminary study to improve the transmission loss of a CFRP panel excited by a synthesised CROR pressure field in lower frequency range. As a first step, a typical aircraft fuselage panel mounted in a sound transmission loss facility is equipped with actuators and sensors to implement multiple-input multiple-output (MIMO) feedforward control of flexural vibration. The CFRP panel is excited via a CROR pressure field synthesised by a 112-channel loud speaker array. The active vibration control (AVC) system is realised by accelerometers and inertial exciters. A considerable vibration reduction of the flexural vibration on the accelerometers is achieved. The local attenuation around the accelerometers leads to a new controlled vibration pattern that radiates sound in a different way than the uncontrolled one. The difficulties in reducing the radiated sound power through the AVC system are due to low observability, the “pinning” effect, and the restructured vibration patterns. All of these effects are studied in detail through surface vibration scans and sound intensity measurements. Additionally, the radiation resistance matrix is used to analyse the controlled vibration patterns.

Item URL in elib:https://elib.dlr.de/89951/
Document Type:Article
Title:Experiments on Active Control of Counter-Rotating Open Rotor Interior Noise
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Haase, ThomasUNSPECIFIEDUNSPECIFIED
Algermissen, StephanUNSPECIFIEDUNSPECIFIED
Unruh, OliverUNSPECIFIEDUNSPECIFIED
Misol, MalteUNSPECIFIEDUNSPECIFIED
Date:February 2014
Journal or Publication Title:Acta acustica united with Acustica
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
DOI :10.3813/AAA.918725
Page Range:pp. 448-457
Publisher:Hirtzel
ISSN:1610-1928
ISBN:Online: 1861-9959 Print: 1610-1928
Status:Published
Keywords:Active control, counter-rotating open rotor
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 - Systems and Cabin
Location: Braunschweig
Institutes and Institutions:Institute of Composite Structures and Adaptive Systems > Adaptronics
Deposited By: Böhringer-Thelen, Isolde
Deposited On:05 Aug 2014 07:59
Last Modified:06 Sep 2019 15:23

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