The Reynolds-averaged Navier-Stokes equations are solved in three dimensions. A model accounts for the turbulent character of the flows. The code is described. Attention is focused on the phenomenon of shock-wave/boundary-layer interaction with separation. The experiments conducted in a transonic channel at ONERA, provide an extended data base required for comparison. In order to reduce the computing resources requirements of the code, a selective switch between single and double precision is used for the flow variables. High rates of vectorization, are achieved on a SIEMENS S600/20 computer. The influence of the initial turbulence level on the numerical results is discussed. Validation based on wall pressure distributions, Mach and skin friction contour lines visualizations and on velocity and turbulent energy profiles, shows good agreement with the experimental data. The standard k-εe model gives better predictions than in two dimensions