Experimental Simulation of Rocket Base Flow using Air as Cold Exhaust Gas in Supersonic External Flow

Kurzfassung

After several investigations were performed to analyze the interaction between hypersonic external flow and the nozzle plume of rocket base flows in the past, now the focus has been set on a supersonic configuration at a freestream velocity of Mach 3. A wind tunnel model representing the generic shape of a launcher has been fabricated to fit the needs of the TMK wind tunnel facility at DLR Cologne. The model with a modular base region has been undertaken different parameter studies with cold air as exhaust gas. High frequency, as well as static pressure measurements in the base region are conducted to characterize the dynamic and static response of the recirculation flow field on different testing conditions. High-speed Schlieren and oil film visualization techniques are used to analyse the flow topology inside the fluid volume as well as directly at the model surface. Pressure fluctuations on the base show characteristic frequencies at Strouhal numbers of 0.2, as well as 1.0 and >1.4.