The Effect of Dynamic Stall on Hingeless Rotors in Hover and Forward Flight

摘要

In this paper the effects of dynamic stall and three-dimensional wakes on a three-bladed isolated hingeless rotor in both hover and forward flight are investigated. The rotor blades are fully nonlinear and allowed in flap-lag-torsional motions. The equilibrium state of blade tip displacements is studied to get insight into the stall effects on rotor-wake coupled system. The ONERA dynamic stall models of lift, drag, and pitching moment for each aerodynamic function of blade and the advanced Finite-State Wake model are utilized. Five modes for each blade degree-of-freedom are chosen. The Galerkin method is applied to analyze the resulting nonlinear equation. The IMSL nonlinear solver is employed to get the steady state solutions. The results are compared and correlated with former results (without dynamic stall effects) to verify the accuracy of our new model. This investigation indicates that the present model predicts larger blade displacements in high pitch angles and high flight speeds. It is suggested that the dynamic stall effects should be considered in such flight conditions.