旋翼飞机的空气动力学对于旋翼飞机而言,很难将常规学科的贡献分得很清楚。特别是柔软旋翼桨叶的运动如此密切地耦合了空气动力学和动力学,所以大部分旋翼的研究和发展工作都必须同时包含这两门学科。因此,以下的内容都有相当部分的叠加,特别是在有关振动的讨论上。下文将给出旋翼飞机的现状与最新进展,并介绍了常规直升机和可变旋翼飞机的挑战和机遇。 现状和最新进展 分析方法 对于常规布局旋翼飞机的性能和低频飞行动力现象,半经验方法一般说来足可以应付使用了,在气动载荷已知的情况下,噪声估算程序也能合理使用。但是正是这些气动载荷难以测定,从而严重地限制了 Aerodynamics of Rotorcraft For rotorcraft, it is difficult to categorize the contributions of conventional disciplines. In particular, the motion of the flexible rotor blades is so closely coupled with aerodynamics and dynamics that most rotorcraft research and development efforts must include both disciplines. Therefore, there is a considerable amount of overlay in the following sections, especially in the discussion of vibration. The status and recent developments of rotorcraft will be given below, as well as the challenges and opportunities for conventional helicopters and variable-rotor aircraft. Status Quo and Recent Developments Analytical Methods Semi-empirical methods are generally adequate for the performance and low-frequency flight dynamics of a conventional rotorcraft. With a known aerodynamic load, the noise estimation procedure can also be used reasonably. However, it is these aerodynamic loads that are difficult to measure and thus severely limited