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The strongly interactive flow field about aircraft afterbodies is investigated using computational techniques by which the thin-shear-layer formulation of the compressible, Reynolds-averaged Navier-Stokes equations is solved. A time-dependent implicit numerical algorithm is used to obtain solutions for a variety of afterbody and nozzle geometries, within the class of bodies of revolution for both subsonic and supersonic external flows and for sonic and supersonic underexpanded jets. Only centered nozzles with either a sharp lip or a blunt base are considered. In all cases, computed results are compared with experimental data. Turbulence closure is realized using algebraic eddy-viscosity concepts. A new and unique adaptive grid technique is used to resolve flow regimes with large gradients and to improve the accuracy and efficiency of the computational scheme. Special singular-point boundary conditions are used for similar purposes and are especially effective for highly underexpanded jets. For the cases considered, the agreement with experimental measurements is very good in invisciddominated regimes and qualitatively good, but less accurate, in regions where there is recirculation. Nomenclaturecalibers D -forebody diameter / = afterbody length, calibers M =Mach number p = pressure r = radial coordinate Re = Reynolds number based on diameter T = temperature U, V = contravariant velocity components X E = end of afterbody %,y = curvilinear coordinates H T = turbulent viscosity coefficient co = vorticity Subscripts J =jet / = local value £,77 = differentiation with respect to £ and 77 oo = freestream condition

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