Experimental study of the dynamic response of a dual throat fluidic thrust vectoring nozzle

Abstract

Dual-Throat Nozzles (DTNs) are a class of fluidic thrust vectoring nozzles in which secondary injection modifies the internal pressure distribution and deflects the primary jet. Although DTN performance has been described in the literature mainly under steady operating conditions, experimental data on transient response remain limited. The present study investigates the dynamic behavior of an axisymmetric DTN during secondary-flow actuation. Experiments were carried out on a facility supplied by a Ludwieg Tube for the primary flow and a compressed-air system for the secondary injection. Wall-pressure signals were acquired synchronously at 51.2 kS/s/ch and ana - lyzed using Savitzky-Golay smoothing and a first-order model with delay fitted to the transient response. Under the investigated operating conditions, the measured response exhibited delayed asymptotic behavior. The dimension-less time constant was determined in order of 9. Pressure oscillations in the kilohertz range were also observed during operation, indicating non-stationary flow phenomena inside the nozzle. The results provide experimentally identified response parameters that can support reduced-order modeling, response-time prediction, and prelimi - nary control-oriented assessment of DTN-based thrust-vectoring systems.