The tail rotor of a helicopter operating under low-speed crosswind undergoes highly complex flow due to the interaction between the main rotor, fuselage, and tail rotor system. In this study, numerical simulations have been conducted on the complete configuration of a helicopter with a ducted fan tail rotor system (comprising a main rotor, ducted fan tail rotor, fuselage, and empennage) to analyze the wake interaction in hovering flight under various crosswind directions. The flow characteristics around the tail rotor, the tail rotor thrust, and the yawing moment of the helicopter are investigated and evaluated. The aerodynamic forces are compared with those of a helicopter with an open-type tail rotor. The results indicate that the aerodynamic performance of the ducted fan tail rotor is highly affected by the wakes of both the main rotor and port wing. Nevertheless, the helicopter with a ducted fan tail rotor is observed to be much more directionally stable under various crosswind directions, than that with an open-type tail rotor. This is because the rotor is protected by the fixed part of the tail rotor system in the former case.

中文翻译：

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低速侧风作用下带风管尾桨旋翼直升机的气动特性

由于主旋翼，机身和尾旋翼系统之间的相互作用，在低速侧风下运行的直升机的尾旋翼经历了非常复杂的流动。在这项研究中，已经对带有导管式风扇尾旋翼系统（包括主旋翼，导管式风扇尾旋翼，机身和尾翼）的直升机的完整配置进行了数值模拟，以分析各种侧风条件下悬停飞行中的尾流相互作用。指示。研究并评估了直升机尾桨周围的流动特性，尾桨推力和偏航力矩。将空气动力与具有开放式尾桨的直升机进行了比较。结果表明，主扇和尾翼的尾流都极大地影响了导管式风扇尾桨的空气动力学性能。尽管如此，与开式尾旋翼相比，带有导管式风扇尾旋翼的直升机在各种侧风方向上的方向稳定性要好得多。这是因为在前一种情况下，转子受到尾部转子系统的固定部分的保护。