直升机机身对旋翼气动干扰的计算

建立了一个全耦合的机身对旋翼气动干扰的迭代计算方法。在该方法中，使用自由涡系模型代表旋翼对干扰流场的影响，使用三维面元模型替代机身的作用，并采用了一个基于“分析数值解匹配”方法的贴近涡／面干扰模型以改进机身引起尾迹畸变的计算。应用该分析方法，以Maryland大学4片桨叶的模型旋翼和机身为算例，计算了悬停和前飞状态机身对旋翼的气动干扰影响。计算结果表明，机身对旋翼气动干扰在悬停和前飞时是不同的，且从悬停至前飞，机身对旋翼平面某方位的诱导速度存在一个从上洗至下洗的过渡。

Prediction of Aerodynamic Interactions of Helicopter Fuselage on Its Rotor

A full coupled and iterative analytical method has been developed to investigate the aerodynamic interaction of a helicopter fuselage on its rotor. The method is used in a rotor free wake model and a 3 D fuselage source panel model to represent the effects of the rotor and fuselage in interactional flow field, respectively. A close vortex/surface interaction model using the analytical/numerical match (ANM) approach is also adopted to improve the calculations on the rotor wake deformation due to the presence of a fuselage. Based upon the analytical method, the aerodynamic interactions of a fuselage on its rotor in hover and forward flight are calculated and analyzed by taking the 4 blade model rotor and fuselage of Maryland University as numerical examples. It is shown that the aerodynamic interactions of a fuselage on its rotor are different in hover and forward flight, and from hover through forward flight, there is a transition from upwash to downwash in the induced velocity of the fuselage on rotor plane.