THE EFFECT OF INITIAL TURBULENCE ON THE EFFICIENCY OF DIFFUSER FLOWS,
FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO
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Experiments were conducted to determine the effect of turbulent exchange in the boundary layer on the efficiency of diffusers with large aperture angles. Turbulence was increased by mounting two perforated plates at the diffuser inlet with openings of 5 and 12 mm spaced at intervals of 6 and 13 mm. A reduction in the intensity of flow separation by gratings was observed visually and confirmed by measurements of the velocity fields at the outlet. Vortex generators are proposed for increasing the intensity of turbulent exchange in the boundary layer to improve diffuser efficiency. Tests of ten types of vortex generators showed no considerable improvement in efficiency.
- Fluid Mechanics