Ground Impingement of a Fan Jet Exhaust Plume
Abstract
This report describes an investigation of the ground impingement properties of a fan jet engine exhaust. Measurements were taken using both a simulated fan jet of laboratory scale and a large scale operating fan jet engine. The results of this work will be used to modify existing models of exhaust-ground interactions to include the unique properties of fan jet impingement on the flow field under a hovering VTOL aircraft, with particular application to the Grumman Design 698. The simulated fan jet exhaust was produced by cold air issuing from a concentric nozzle and utilizing a screen in the inner section to develop the lower dynamic pressure that is characteristic of a real fan jet engine. Measurements taken during impingement of the jet engine exhaust consisted of pitot pressure profiles above the ground. Wall jet velocity profiles obtained in these two impingement flows showed close agreement when scaled by size and nozzle pressure ratio. This favorable comparison demonstrates the effectiveness of using cold air, scale model flows to simulate the impingement flow field of a real fan jet engine exhaust. The effects on the impingement flow of an immersed control vane were investigated in both the simulated and the fan jet engine exhausts.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1978
- Accession Number
- ADA054832
Entities
People
- Richard C. Jenkins
- William G. Hill Jr.
Organizations
- Grumman