Application of Back-Step Coanda Flap for the Supersonic Co-flowing Fluidic Thrust Vector Control

The present technique controls the thrust-vectoring of a supersonic primary jet by utilizing coanda effects of the secondary jet exhausted parallelly at the nozzle exit. A multicomponent force measurement system of a high accuracy has been developed to quantitatively evaluate the performance of the present fluidic thrust vector control technique. Detailed calibration and data analysis have been performed to reveal that the overall measurement error is as small as 5%. Quantitative test results of thrust vectoring with the flow visualizations are provided. Some limitations in the application of the technique have been noticed, and thus the new method utilizing backward-step coanda flaps has been tried. It is found that the back-stepped coanda flap with smaller value of the height of secondary jet can enhance the coanda effects of the primary jet flow with less consumption of the control mass flow rate. Linear response of the deflection angle to the pressure of the secondary jet is also observed, with limited small deflection angles.