Contents
What are the boundary layers in subsonic flow?
Turbulent Boundary Layers in Subsonic and Supersonic Flow (AGARD AG-335) Executive Summary
Where is the ingestion of boundary layer air?
The new propulsor design, meaning the inlet and the fan, is embedded in the aircraft body at the back of the fuselage and ingests the slower boundary layer air flow, using it to generate the thrust needed to propel the aircraft through its mission.
How does boundary layer ingestion improve fuel efficiency?
This animation shows an engine inlet and fan ingesting boundary layer air in a wind tunnel. Analytical studies have shown that boundary layer ingesting propulsors have the potential to improve aircraft fuel efficiency.
Where is boundary layer ingestion propulsion being tested?
Engineers at NASA’s Glenn Research Center in Cleveland are testing a new kind of propulsion system using a principle called Boundary Layer Ingestion. Analytical studies have shown that this new technology has the potential to reduce the aircraft fuel burn by as much as 8.5% compared to aircraft flown today.
How does Reynolds number affect subsonic boundary layer?
For subsonic flows, Reynolds number can have a significant effect on the level of the maximum turbulence stresses, and the location of that maximum in the boundary layer. The properties of the organised structures are dependent on the Reynolds number.
What are the effects of compressibility on supersonic flow?
For supersonic flows at moderate Mach numbers, it appears that the direct effects of compressibility on wall turbulence are rather small. It is noted that certain characteristics cannot be collapsed by simple density scaling, and that the existing data indicates that longitudinal space scales fall sharply with Mach number.
How are temperature gradients found in the boundary layer?
Furthermore, the temperature gradients which are found in the boundary layer in supersonic flow lead to variations in Reynolds number acmss the layer which must be con- sidered along with the usual variations in the streamwise direction. We begin this report by reviewing the boundary layer equations in Section 2.