Numerical investigation of supersonic inlets for ramjets

Kurzfassung

The Parameters,models and schemes affecting the stable and accurate resolution of a pseudo-shock system when numerically computing the strong ad- , models and schemes affecting the stable and accurate resoluverse pressure gradient flow for a supersonic inlet for ramjet applications with the DLR TAU code have been investigated. Concomitantly, a stabilizing technique for the start-up phase of the computation on two-dimensional domains of reduced length, where the backpressure is imposed directly at the outlet, has been assessed. This allows to spare grid size by a significant amount, avoiding the need of a second throat bringing the flow to supersonic conditions at the outlet, and it could be an advantage during preliminary design studies. At the same time, it leads to ill-posedness of the problem, therefrom the need of a stabilizing technique during start-up and improvement of the stability parameters. Two inlet configurations have been studied at a design Mach number of 3 for increasing values of the backpressure: a base configuration without bleed and a bleed configuration featuring a boundary layer bleeding slot on the bottom wall. Results have been compared to experimental data and schlieren visualizations.