Investigation of noise produced by electric Boundary Layer Ingesting ducted fans in future aircraft

What is it about?

Our first-of-its-kind study at the University of Bristol’s National Aeroacoustic Wind Tunnel Facility revealed for the first time how noise is generated and propagated from embedded engines, technically known as boundary layer ingesting (BLI) ducted fans. BLI ducted fans are similar to the large engines found in modern airplanes but are partially embedded into the plane's main body instead of under the wings. As they ingest air from both the front and from the surface of the airframe, they don't have to work as hard to move the plane, so it burns less fuel. We dissected the noise using a source decomposition method into components including fan and duct aeroacoustics and airframe boundary layer flow interactions. The approach provides a clear understanding of the underlying physics of noise origin and variation with different thrust levels of BLI ducted fans.

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Photo by Hyundai Motor Group on Unsplash

Photo by Hyundai Motor Group on Unsplash

Why is it important?

Our study addresses this urgent issue of noise, which poses a major obstacle in obtaining certifications for future aircraft, by uncovering the physics behind the noise these configurations produce. Understanding the noise mechanisms in BLI ducted fans is critical for developing quieter aircraft. With increasing demand for silent aircraft to enhance flight experience with minimal environmental impact, this research could help shape strategies to reduce noise emissions in the aviation sector.

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