Assessment of transition regimes in a dual-bell nozzle and possibility of active fluidic control

Dual-bell axisymmetric propulsive nozzle, as the most prominent altitude compensating nozzle concept has been investigated for transition modes and effects. Experimental and numerical investigations show that dual-bell nozzle can be very effective for desired large envelope launcher stage trajectories. Transition regimes are studied in the high altitude simulation wind-tunnel and supported by the numerical simulations. Analysis of the employed diagnostics shows an existing particular hysteresis between the transitioning modes and pinpoints to possibilities to control the early transition. Further numerical investigation on active flow control indicates the promising potentials of the proposed fluidic injection system.