THEORETICAL-ANALYSIS OF AIRCRAFT AFTERBODY FLOW

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. 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.