采用综合气弹分析方法的旋翼非定常气动载荷计算

提出一种桨叶结构、气动和惯性耦合的旋翼系统综合分析方法，将桨叶绕挥舞、摆振及变距铰的刚性转角作为广义坐标，计入了桨叶整体运动和自身中等弹性变形之间的动力学耦合效应，桨叶弹性变量通过有限元法进行离散，翼型剖面气动力采用Leishman—Beddoes二维非定常和动态失速模型，由自由尾迹模型得出桨盘的非均匀入流，依据柔性多体系统动力学方法推早出桨叶前飞状态下的非线性周期时变动力学方程。对Newmark隐式数值积分方法进行改进，用于求解旋翼桨叶的响应。以法国SA349／2小羚羊直升机的试飞测试数据为依据，验证了方法的有效性。

Unsteady Rotor Airload Prediction Using a Comprehensive Aeroelastic Analysis

An accurate prediction for helicopter rotor loadings requires detail analyses with both sophisticated structural and aerodynamic capabilities. This paper presents a comprehensive analysis for a coupled rotor system incorporated consistent blade structural, aerodynamic and inertial couplings. Using the rigid rotations of the blade about the flap, lag and pitch hinges as general coordinates, it accounts for the dynamic coupling effect between the rigid motion of the blade and moderately large elastic deflections discretized by a finite element formulation. A nonlinear aerodynamic analysis for attached flow, separated flow and dynamic stall based on the work of Leishman and Beddoes is incorporated and used to investigate rotor blade section airloads. The inflow is evaluated with the free wake analysis. The equations of motion for the nonlinear periodic time variant system are derived based on the dynamics of flexible multibody systems. A modified implicit Newmark scheme is used to calculate blade response as one coupled solution. Results are corrected with SA349/2 Aerospatiale Gazelle flight test data. The blade airloads and the flap angles predicted by the analysis show that the flight test data are efficient.