A numerical study of the starting process in a hypersonic shock tunnel

This dissertation represents the first time calculations have been made of the unsteady viscous simulation of the starting process in a hypersonic shock tunnel including the bifurcation phenomenon due to the interaction of the reflected shock with the boundary layer generated by the incident shock in the shock tube.; In order to simulate the unsteady viscous flow in the NASA Ames 16-inch hypersonic shock tunnel, which consists of axisymmetric shapes (shock tube and nozzle), rectangular shape (test cabin) and octagonal shape (diffuser), a time-dependent ADI (Alternating Direction Implicit) axisymmetric full Navier-Stokes code with a second order upwind TVD (Total Variation Diminishing) scheme and a time-dependent three-dimensional thin layer Navier-Stokes code with an explicit MacCormack TVD scheme have been developed. As shown in the code validation study, these Navier-Stokes codes with the high resolution TVD algorithms give fair agreement with available experimental data and exact solutions.; Numerical simulations of the starting process for the NASA Ames 16-inch Hypersonic shock tunnel show that during the reflected shock interaction process at the end of the shock tube, the bifurcation phenomenon, and the strong vortices become dominant features. The vortices due to the reflected shock interactions appear in the axisymmetric simulation but are not generated in the two-dimensional flow.; For the nominal testing condition, the starting process in the NASA Ames shock tunnel takes 1700 {dollar}mu{dollar} sec. The required total testing time consists of the time for the starting process, 1.7 m sec, and the time for the flow establishment over a model in the test cabin which strongly depends on the model shape and size and model mounting location. For a 15{dollar}spcirc{dollar}-cone model, the minimum required testing time is estimated as at least 2.7 m sec for the steady state.