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The effects of surface mass transfer on the flowfield around sharp slender cones at zero angle of attack in low-density supersonic and hypersonic flow are computed using an iterative inviscid-viscous flowfield calculation model. The perfect gas model that is developed considers nonsimilar binary gas boundary layers, viscous interaction, transverse curvature, wall slip, and temperature jump. The inviscid and viscous flowfields are matched using a displacement thickness, which includes the effects of surface mass transfer, and the inviscid flow is computed using either the tangent cone theory or the conical shock expansion theory. Calculated effects of helium, argon, carbon dioxide, and air injection on total drag values and surface pressure distributions are compared with experimental data at Mach 3.93 and JReco/in. ^1800, Mach 5.64 and JRe^/in. ~6300, and Mach ~10 and Ke^/in. ~400, 1700, and 2700. The numerical results and experimental data agree well except at the low-density Mach ^10, Re^/in. 4CO condition where noxicontmuuirL and other very low-density effects become important. Also presented are some calculated displacement thickness and velocity profile results.Nomenclature $ CD/ = skin-friction drag coefficient (referenced to base area) €DP = pressure drag coefficient GDI = total drag coefficient (<7z>/ + CD P ) HQ = freestream stagnation enthalpy M = Mach number m = mass transfer rate p = static pressure R = gas constant Re = Reynolds number r = radius normal to axis of symmetry T = temperature TO = freestream stagnation temperature Uao = freestream velocity u = tangential velocity component v = normal velocity component x = surface distance from cone apex y = distance normal to cone surface 5 = boundary-layer thickness Sm* = displacement thickness including the effect of surface mass transfer B c = cone half-angle jj, = dynamic viscosity p = mass density Subscripts e = inviscid conditions at "edge" of boundary layer w = wall conditions co = freestream conditions

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