Fluidic Thrust Vectoring: CFD Analysis of Secondary Injection in Convergent-Divergent Nozzles

Secondary flow injection for thrust vectoring offers a simple alternative to mechanical thrust vectoring systems by redirecting the exhaust flow, without using any moving parts. This study conducts a computational fluid dynamics (CFD) analysis of secondary injection in an axisymmetric convergent–divergent (C–D) nozzle with ANSYS Fluent 2025 R2. A density based solver with the SST k–ω turbulence model was utilized for assessing the application of a nozzle pressure ratio (NPR = 2.67) and secondary pressure ratio (SPR = 1.05) on flow behavior and vectoring performance while using the converging nozzle as the injection area. The results show that secondary injection results in the formation of asymmetric flow structures and oblique shock in the divergent section with a maximum Mach number of 1.72 and jet deflection angle of ≈6.8° and thrust loss less than 3 %. The static pressure ratio in the vicinity of the injector region was approximately (≈1.05–1.07) is similar to previous studies, indicating that the numerical model is accurate. The findings of this study support that secondary injection increases thrust control and maneuverability while decreasing structural complexity, indicating that fluidic thrust vectoring can provide a potential technology for future Unmanned Aerial Vehicle (UAV), missiles, and supersonic aircraft propulsion system