Optimization of Mass Bleed for Base-Drag Reduction
Efficient mass-bleed conditions to minimize base drag are examined in consideration of various base-to-orifice-exit area ratios for a body of revolution in the Mach 2.47 freestream. Axisymmetric, compressible, mass-averaged Navier-Stokes equations are solved using the standard k-w turbulence model, a fully implicit finite volume scheme, and a second-order upwind scheme. Base flow characteristics are explained regarding the base configuration as well as the injection parameter, which is defined as the mass flow rate of the bleed jet nondimensionalized by the product of the base area and freestream mass flux. The results obtained through the present study show that for a smaller base area, the optimum mass-bleed condition leading to minimum base drag occurs at relatively larger mass bleed, and a larger orifice exit can offer better drag control.