Improvements in Modeling 90-Degree Bleed Holes for Supersonic Inlets

摘要

The modeling of porous bleed regions as boundary conditions in computational fluid dynamics simulations of supersonic inlet flows has been improved through a scaling of sonic flow coefficient data for 90-deg 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 in which the only factor was the ratio of the plenum static pressure to the surface static pressure. This simplified the implementation of the bleed model into a computational flow solver by no longer requiring the evaluation of the flow properties at the edge of the boundary layer. The quadratic equation allows extrapolation at higher plenum pressure ratios, which allows for the modeling of small amounts of blowing, which can exist when recirculation of the bleed flow occurs within the bleed region. The model was demonstrated for computational simulations of supersonic flow over a flat plate with a porous bleed region with and without an impinging shock wave. The computed sonic flow coefficients showed improvement over the previous porous bleed model in comparison with experimental data and three-dimensional computational simulations of flow through the bleed holes and bleed plenum.