Improvements in Modeling 90-degree Bleed Holes for Supersonic Inlets

Abstract

The modeling of porous bleed regions as boundary conditions in computational fluid dynamics (CFD) simulations of supersonic inlet flows has been improved through a scaling of sonic flow coefficient data for 90-degree bleed holes. The scaling removed the Mach number as a factor in computing the sonic flow coefficient and allowed the data to be fitted with a quadratic equation with the only factor being the ratio of the plenum static pressure to the surface static pressure. This simplified the implementation of the bleed model into the Wind-US CFD flow solver by no longer requiring the evaluation of the flow properties at the edge of the boundary layer. The quadratic equation can be extrapolated to allow the modeling of small amounts of blowing, which can exist when recirculation of the bleed flow occurs within the bleed region. The improved accuracy of the bleed model was demonstrated through CFD simulations of bleed regions on a flat plate in supersonic flow with and without an impinging oblique shock. The bleed model demonstrated good agreement with experimental data and three-dimensional CFD simulations of bleed holes.