Open and Closed-Loop Responses of a Dual-Throat Nozzle during Fluidic Thrust Vectoring

The dynamic response of a Dual-Throat Nozzle in open and closed-loop control is investigate numerically. Thrust vectoring in fixed, symmetric nozzles is obtained by secondary flow injections that cause local flow separations, asymmetric pressure distributions and the vectoring of primary jet flow. The computational technique is based on a model for the compressible URANS equations. A minimal control system governs the unsteady blowing. Nozzle performances and thrust vector angles have been computed for a wide range of nozzle pressure ratios and secondary flow injection rates. The numerical results are compared with the experimental data available in the open literature. Several computations of the open-loop dynamics of the nozzle under different forcing have been performed in order to investigate the system response in terms of thrust vectoring effectiveness and controllability. These computations have been used to extract ARX models of the nozzle dynamics. The effects of including the actuator dynamics are also discussed. Simple strategies of closed-loop control of the nozzle system by PID regulators are investigated numerically. The closed-loop Model Predictive Control of the system, based on the ARX models, is addressed.