Trailing-Edge Beveling Effect on Passive Fluidic Thrust Vectoring Nozzle Jet Deflection Control

Passive fluidic thrust vectoring nozzles feature a simple structure and low energy consumption. However, traditional 2D passive fluidic thrust vectoring nozzle suffers from jump and control reversal in thrust angle. This study proposes a trailing-edge beveled passive fluidic thrust vectoring nozzle which weakens the jump in thrust vector angle and eliminates control reversal. Experiments were conducted to obtain force angle control characteristics and jet flow structures. Results show that trailing-edge bevel angle significantly affects jet deflection control characteristics: 0° (2D nozzle) and 15° nozzles have obvious thrust vector angle jumps and control reversal, while 30°, 45°, and 60° nozzles eliminate abrupt jumps and no control reversal. However, the maximum thrust vector angle decreases gradually with increasing bevel angle. Then 2D nozzle and typical 45° trailing-edge beveled nozzle were selected for investigation. For 2D nozzle, as secondary flow channel opening difference (δ) increases, all spanwise jets deflect synchronously at δ = 0.58, generating an uncontrolled jump and entering a supercritical state in thrust vector angle. In the range of δ = 0.58~1 the supercritical state diminishes, leading to control reversal. While for 45° beveled nozzle, at δ = 0.35, the jet deflects only at the short side, which weakens thrust vector angle jump. In the range of δ = 0.35~1, jet deflection region expands and produces normal force continuously, which eliminates the thrust vector angle control reversal. The jet deflection region of the beveled nozzle has a smaller spanwise proportion than that of the 2D nozzle, resulting in a reduced maximum vectoring angle. The results show the influence of trailing-edge beveling effect on the flow structure and jet deflection control characteristics under low-speed conditions, yielding valuable insights for the optimization of the design of passive FTVC nozzles.