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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. ISSN 1610-1928.

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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
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Date:February 2014
Journal or Publication Title:Acta acustica united with Acustica
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:No
Page Range:pp. 448-457
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 (old)
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:29 Nov 2023 08:35

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