The disadvantage is that the interaction between the jet, flow, and the boundary layer developing on the fuselage of the body is so complex that the prediction of the resulting forces becomes difficult. According to the configuration of the jet, its position on the missile, or the jet pressure ratio, an amplification of the jet is possible as well as a diminution
In the frame of the DLR-internal project of the “High agile Missle” (HaFK) a study was carried out that encompassed an extensive set of measurements in the Ludwieg Tube (RWG) of the DLR on a principle model as well as numerical calculations with the DLR-TAU-code. The latter were conducted on chosen cases for comparison purposes and for the validation of the applied code. For this purpose, the same initial and boundary conditions were chosen. Initially, a flat plate was used and a sonic nozzle mounted centred on the plate and exposed to a Mach 5 flow. With this setup it was possible to simulate different jet configurations and their different effects. Surface pressure measurements and flow visualisations with oil flow method gave insights about the effect in the vicinity of the interaction area. The usage of infrared cameras and the according analysis allowed the determination of the heat flux, which strongly varies in the interaction areas and results in strong temperature loads on material and structure. This study enabled a systematic investigation of the side jet control with regard to different jet configurations and their effectiveness.