EXPERIMENTAL AND NUMERICAL INVESTIGATION OF THE TURBULENT WAKE FLOW OF A GENERIC SPACE LAUNCHER CONFIGURATION

The turbulent wake of a generic space launcher at cold hypersonic free-stream conditions is investigated experimentally and numerically to gain detailed insight into the intricate base §ow phenomena of space vehicles at upper stages of the §ight trajectory. The experiments are done at Ma ∞ = 6 and ReD = 1.7 · 106 m−1 by the German Aerospace Center (DLR) and the corresponding computations are performed by the Insti-tute of Aerodynamics Aachen using a zonal Reynolds-averaged Navier Stokes / Large-Eddy Simulation (RANS/LES) approach. Two di¨erent aft-body geometries consisting of a blunt base and an attached cylin-drical nozzle dummy are considered. It is found that the wind tunnel model support attached to the upper side of the main body has a non-negligible impact on the wake along the whole circumference, albeit on the opposite side, the e¨ects are minimal compared to an axisym-metric con¦guration. In the blunt-base case, the turbulent supersonic boundary layer undergoes a strong aftexpansion on the model shoulder leading to the formation of a con¦ned low-pressure (p/p ∞ ≈ 0.2) re-circulation region. Adding a nozzle dummy causes the shear layer to reattach on the its wall at x/D ∼ 0.6 and the base pressure level to increase (p/p ∞ ≈ 0.25) compared to the blunt-base case. For both con-¦gurations, the pressure §uctuations on the base wall feature dominant frequencies at SrD ≈ 0.05 and SrD ≈ 0.20.27, but are of small am-plitudes (prms/p ∞ = 0.020.025) compared to the main body boundary layer. For the nozzle dummy con¦guration, when moving downstream along the nozzle extension, the wall pressure is increasingly in§uenced by the reattaching shear layer and the periodic low-frequency behavio