Overview
The objective of the activity under this CfP was the test of a full-scale Main Landing Gear fuselage-mounted architecture sized for a high-wing regional aircraft configuration in a Wind Tunnel facility. This proposal considered a complete architecture including all necessary features from an aero-acoustic point of view including gear struts, wheel pack, bay cavity and doors, fairings and portion of fuselage.
A low noise technology was investigated following a selection process to be completed within GRA activities. The concept of an acoustic mirror was developed resulting in a design which enabled accurate far field sound measurements via a sectioned model with an acoustic reflector on the half plane. The consortium designed and manufactured a modular full-scale mock-up of the MLG integrating low-noise devices as indicated from the GRA ITD Member. The model was modular in order to test both the baseline and the low-noise MLG architecture with one or both gear legs.
Advanced aero-acoustic measures including partial coherence techniques, orthogonal beam forming, and deconvolution beam forming were utilised to fully assess the noise emission of the landing gear. These techniques quantified the source distribution, mechanisms of noise reduction and provided an innovative tool for use in aeroacoustic problems of this nature.
ARTIC has put together a consortium which comprised of one of Europe's most distinguished Universities, a Research Institute in aeronautics of international renown and an SME with specific competence in aerospace design, manufacturing and structural analysis. All partners have participated and delivered in EU projects, in some cases extensively including coordination. In addition, subcontracting was given to the only aero-acoustic wind tunnel company in Europe capable to perform these tests.
Funding
Results
Executive Summary:
The ARTIC project had been developed in response to the requirements of the European Clean Sky Joint Technology Initiative to assess low noise technologies applied to main landing gear architectures. ARTIC has put together a consortium led by Trinity College Dublin, a well-known European research centre NLR and SME partner INASCO. This group has well demonstrated competencies in wind tunnel model design and manufacturing, experimental aeroacoustics, noise measurements and data analysis.
The objective of the activity under this CfP was the test of a full-scale main landing gear (MLG), fuselage mounted and sized for a high-wing regional aircraft configuration. A novel low noise technology was utilised to achieve a noise reduction over the base line configuration. Extensive aero-acoustic tests were planned in one of Europe’s leading wind tunnels, DNW’s Large Low-speed Facility. This is the only aero-acoustic wind tunnel in Europe with a test section of sufficient size to complete this investigation.
The key characteristics associated with the landing gear noise problem were:
- Contributes to approximately 30% of the overall noise emission of the aircraft during take-off and approach phases;
- The noise signature is broadband in nature covering frequencies from approximately 90Hz to 4KHz;
- The annoyance level associated with noise within this frequency range is high for exposed communities;
- Landing gear consists of numerous structures, surfaces and components which are generally not optimised from an aero-acoustic point of view;
- Turbulence from non-aerodynamic components of the landing gear is a direct noise source;
- The wake of the landing gear structures can interact with other airframe components and generate an indirect noise source.
In the past full-scale models of landing gears have rarely been tested due to the large test facilities required. Most experimental airframe noise research had been performed using small-scale models. This leads to great difficulty when using model-scale results for full-scale noise predictions due to the lack of details in the geometrical modelling. One of the significant contributions of ARTIC was that a full representation of the landing gear detail and associated structures (e.g. bay cavity, bay doors, belly fuselage etc.) was to be included and addressed at full scale. The output designs of the low noise down selection made at the GRA level had been received by ARTIC and implemented on the designed wind tunnel model.
The ARTIC project successfully completed its design phase. A number of numerical codes were also developed in preparation for the wind tunnel test analysis. However, despite a significant extension, the SME partner INASCO was unable to complete the manufacture of the model. ARTIC therefore ended without a wind tunnel test campaign.