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首页> 外文期刊>Journal of the American Helicopter Society >Main Rotor-Tail Rotor Interaction and Its Implications for Helicopter Directional Control
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Main Rotor-Tail Rotor Interaction and Its Implications for Helicopter Directional Control

机译：主旋翼-尾旋翼相互作用及其对直升机方向控制的启示

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Aerodynamic interference between the main and tail rotor can have a strong negative influence on the flight mechanics of a conventional helicopter. Significant unsteadiness in the tail rotor loading is encountered under certain flight conditions,-but the character of the unsteadiness can depend on the direction of rotation of the tail rotor. Numerical simulations, using Brown's vorticity transport model, of the aerodynamic interaction between the main and tail rotors of a helicopter are presented for a range of forward and lateral flight trajectories. Distinct differences are predicted in the behavior of the system in left and right sideward flight that are consistent with flight experience that the greatest fluctuations in loading or control input are required in left sideways flight (for a counterclockwise rotating main rotor). These fluctuations are generally more extreme for a system with tail rotor rotating top-forward than top-aft. Differences are also exposed in the character of the lateral excitation of the system as forward flight speed is varied. The observed behavior appears to originate in the disruption of the tail rotor wake that is induced by its entrain men t into the wake of the main rotor. The extent of the disruption is dependent on flight condition, and the unsteadiness of the process depends on the direction of rotation of the tail rotor. In intermediate-speed forward flight and right sideward flight, the free stream delays the entrainment of the tail rotor wake far enough downstream for the perturbations to the rotor loading to be slight. Conversely, in left sideward and quartering flight, the free stream confines the entrainment process close to the rotors, where it causes significant unsteadiness in the loads produced by the system.
机译：主旋翼和尾旋翼之间的空气动力干扰会对常规直升机的飞行力学产生很大的负面影响。在某些飞行条件下，尾桨负载会出现明显的不稳定，但是不稳定的特性可能取决于尾桨的旋转方向。利用布朗的涡度传输模型，对一系列向前和向后的飞行轨迹进行了直升机主旋翼和尾旋翼之间的气动相互作用的数值模拟。预测系统在左右飞行中的行为会出现明显差异，这与飞行经验一致，即在左飞行中需要最大负载或控制输入波动（对于逆时针旋转的主旋翼）。对于尾桨从上到下旋转而不是从后到上旋转的系统，这些波动通常更为严重。随着前向飞行速度的变化，系统的横向激励特性也暴露出差异。观察到的行为似乎源自尾旋翼尾流的破坏，尾旋翼尾流是由其夹带进入主旋翼尾流引起的。扰动的程度取决于飞行条件，过程的不稳定性取决于尾桨的旋转方向。在中速向前飞行和向右飞行中，自由流将尾旋翼尾流的夹带延迟到足够远的下游，以使对旋翼载荷的扰动很小。相反，在左侧飞行和四分之一飞行中，自由流将夹带过程限制在靠近转子的位置，这会导致系统产生的负载明显不稳定。

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