GARDN - Airframe Noise Reduction

In order to meet increasingly stringent noise certification limits and airport noise limitations, future aircraft will need to take innovative approaches to reduce airframe noise. The major contributors to airframe noise are... [ view full abstract ]

In order to meet increasingly stringent noise certification limits and airport noise limitations, future aircraft will need to take innovative approaches to reduce airframe noise. The major contributors to airframe noise are the landing gear and the high-lift system (flaps and slats). This project focused on ways to predict and to reduce the noise of these different sources and is planned to progress various technologies from TRL 3 through TRL 6.
Landing Gear Noise Reduction

Due to the lack of aerodynamic refinement, landing gears are often the noisiest airframe component but, conversely, are the most amenable to noise reduction measures.

Bombardier Aerospace and Heroux-Devtek collaborated to perform wind tunnel testing of a full scale landing gear model with NRC and the DNW. Results were modeled and analyzed. Initial focus has been on validating and enhancing computational aeroacoustics techniques. The next steps will be to evaluate noise reduction technologies that can be practically applied to current and future designs. Lastly semi-empirical models are being developed that can be used during early design stage evaluations when quick design reviews are required.

High-Lift System Noise Reduction

Despite extensive research conducted on flap/slat noise in Europe and the US over the last ten years, no clearly superior noise reduction method has emerged that can be practically applied to aircraft.

To aid in the work Bombardier collaborated with Aercoustics to refurbish the University of Toronto Institute for Aerospace Studies anechoic wind tunnel. Testing performed provided insight into the flap and slat noise generation mechanisms and multiple solutions were developed and tested.

Bombardier also performed microphone methodology development and testing to identify the key airframe noise sources.

In this paper an update on the progress achieved in this project is to be presented as well as the next phases of the project and future applications in BA will be presented.