Flowfield Structure and Aerodynamic Characteristics of Twin Transverse Jets in Low-Density Hypersonic Crossflow

Under low-density hypersonic flight conditions, conventional aerodynamic control authority is markedly reduced, making transverse jets a promising approach for direct force control. However, the interaction mechanisms of multiple jets under such conditions remain unclear. In this paper, numerical simulations were employed to investigate the flowfield structure, aerodynamic characteristics, and their coupling-induced variations in twin transverse jets under low-density hypersonic crossflow. The results show that the twin-jet flow is not a simple superposition of two isolated single jets, but exhibits distinct near-wall separation, compression, and wake evolution patterns induced by jet–jet interaction. The upstream jet aerodynamically shields the downstream injector, modifies its local crossflow conditions, and consequently enhances downstream jet penetration and wake development. Conversely, the downstream jet affects the upstream flow through the near-wall boundary layer by pushing the primary separation region farther upstream, restricting the free expansion of the upstream jet, and intensifying compression and recirculation in the inter-jet and near-wake regions. Macroscopically, the aerodynamic force analysis reveals that the control force coefficient increases with jet strength, whereas the control force amplification factor decreases continuously. Compared with a single-jet configuration at matched total jet mass flow rate, the twin-jet configuration yields a higher control force and a lower total moment. These findings provide fundamental physical insights into the design and optimization of multi-jet direct force control systems under low-density hypersonic flows.