The aerodynamic characteristics have been studied of a wide bleed slot in the presence of a terminal shock wave in a simulation of the bleed arrangements employed at the throat of some external compression intakes on supersonic aircraft. The problem was to investigate the nature of the flow field above the slot and to determine the governing flow mechanism. A comprehensive series of measurements, together with a theoretical study of the essentially inviscid nature of any shock wave/free shear layer interaction have led to the formulation of an inviscid model of the flow field which exhibited the correct relationship between primary flow, bleed flow, shock geometry and cavity pressure. The bleed flow itself is contained in the shear layer which emanates from the front lip and separates the high speed primary flow from the nearly stagnant air in the void. An experimental exploration of the shear layer was also carried out and the shear layer properties were incorporated into the inviscid model to give estimates of bleed flow total pressure immediately prior to its entry and diffusion into the bleed cavity. This has given a realistic criterion on which to base estimates of bleed diffusion efficiency.
|Date of Award||1974|