Development of Boeing-Vertol Dynamic Stall Model Considering Unsteady Flow Effects

In precision of the aerodynamic coefficients, modification and development of the Boeing-Vertol model are the main goal of the presented paper in which unsteady wake effects are considered. Hence, this paper uses based on Wagner function to consider the unsteady wake effects and to introduce an effective angle of airfoil degrees of freedom and their derivatives for both bending and pitching oscillations. The aerodynamic lift coefficient of the Boeing- model is improved by using the introduced effective angle of attack and flow apparent mass effects. Also, a new pitching moment coefficient is introduced and is replaced in the model. The introduced aerodynamic coefficients are validated and verified by experimental data and also compared with the original model. The obtained results represent correction of the lift coefficient of the Boeing Vertol model in of the static lift curve and improvement of maximum lift coefficient and of . Also, the results show that the proposed formulation enhances the Boeing Vertol model to predict moment coefficient in dynamic condition. In addition, a parametric study is conducted to investigate the effects of reduced frequency on effective angle of attack and it is shown that while reduced frequency increases to 0.36, unsteady wake effects on effective angle of attack of an airfoil reach to its maximum value. Moreover, for reduced frequencies upper than 0.1, pitch axis location changes the characteristics of the effective angle of attack of the airfoil.