A computational investigation was conducted to optimize the fluidic injection angle effects on thrust vectoring. Numerical simulation of fluidic injection for shock vector control, with a convergent-divergent nozzle concept was performed, using URANS approach with Spalart-Allmaras turbulence model. The fluidic injection angles from 60º to 120º were investigated at different aerodynamic and geometric conditions. The current investigation demonstrated that secondary injection angle is an essential parameter in fluidic thrust vectoring. Computational results indicated that, optimizing secondary injection angle would have positive impact on thrust vectoring performance. Furthermore, in most cases, decreasing expansion ratio of the nozzle with increasing NPR has negative impact on pitch thrust vector angle and thrust vectoring efficiency. That is, the highest pitch thrust vector angle is obtained by decreasing nozzle expansion ratio with increasing SPR in smaller fluidic injection angles. In addition, the current investigation attempted to initiate a database of optimized injection angles with different essential parameter effects on thrust vectoring, in order to guide the design and development of an efficient propulsion system.

The present study attempted to utilize a computational investigation to optimize the external freestream flow influence on thrust-vector control. The external flow with different Mach numbers from 0.05 to 1.1 and with optimum injection angles from 60˚ to 120˚ were studied at variable flow conditions. Simulation of a converging-diverging nozzle with shock-vector control method was performed, using the unsteady Reynoldsaveraged Navier-Stokes approach with Spalart-Allmaras turbulence model. This research established that freestream flow and fluidic-injection angle are the significant parameters on shock-vector control performance. Computational results indicate that, increasing freestream Mach number would decline the thrust vectoring effectiveness. Also, optimizing injection angle would reduce the negative effect of external freestream flow on thrust-vector control. Moreover, increasing secondary to primary total pressure ratios and decreasing nozzle pressure ratios at different freestream Mach number would decrease dynamic response of starting thrust-vector control. Additionally, to lead the improvement of the next generation of jet engine concepts, the current study aimed to originate a database of variable external flow with effective aerodynamic parameters, which have influence on fluidic thrust-vector control.