An Investigation of the Ejector-Powered Jet-Flap

Author: Sidor, Laurent Bernard

Year: 1974

Degree: Engineer's thesis

Advisors: Stewart, Homer Joseph; Harris, Gordon L.

Committee Member: Unknown, Unknown

Option: Aeronautics

DOI: 10.7907/D5X4-X160

Abstract

The inviscid and incompressible potential flow aspects associated with a two-dimensional ejector-powered jet-flap configuration are investigated. The energy addition due to the mixing process in the ejector results in a non-homogeneous flow and is represented by an actuator disk located between the lifting surfaces and a powered wake. A set of singularities is developed to represent the lifting surfaces, to include camber and flap deflection, and the powered wake. A numerical procedure is used to compute the total system vorticity needed to satisfy exactly all the prescribed boundary conditions. The lift and moment coefficients are evaluated as a function of the head change prescribed across the actuator disk. A simple interpretation of the resulting lift curves is proposed in terms of analytical results obtained for single-airfoil configurations - a flat-plate airfoil and sink system, and a conventional single element jet flap. The sink effect of the actuator accounts for a finite lift at zero angle of attack, and the lift increment due to angle of attack only can be predicted by using Spence's theory of the jet flap.

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