Abstract
Experimental and numerical investigations of jet oscillation in a dual-bell at a low-altitude operation mode are carried out. At the low-altitude operation mode, a supersonic jet separates at an inflection point of the dual-bell nozzle. An axial mode and two diametrical mode of the jet oscillation occur. Up to now, the cause of the axial mode has not been clarified. Numerical simulations with flow excitation are carried out. It is confirmed that the jet oscillation occurs due to acoustic resonance. Additionally, interactions between the separated jet and a film cooling flow are investigated. The experimental and numerical result show that the film cooling flow excites the main jet oscillation at the low-altitude operation mode.
