The coupled flap-lag-torsion aeroelastic response and stability of multibladed hingeless rotors in the hovering flight condition are investigated. The vortex lattice method, with a three-dimensional prescribed wake geometry, is used for the prediction of unsteady airloads of multibladed rotors undergoing disturbed dynamic motions. Interblade unsteady wake effects due to the vortex-phasing phenomena beneath a rotor are numerically calculated by the phase control of wake vortices shed from each blade. The aeroelastic equations of motion of the rotor blade are formulated using a finite element beam model (FEM) that has no artificial restrictions on the magnitudes of displacements and rotations due to the degree of nonlinearity. Numerical results of the steady equilibrium deflections and the lead-lag damping and frequency are presented for two-, three-, and four-bladed stiff-inplane rotors, and are compared with those obtained from a two-dimensional quasisteady strip theory with steady and uniform inflow. The results show that the three-dimensional tip and realistic wake effects greatly affect the steady equilibrium and the rotor stability. It is espacially found that the unsteady wake inflow dynamics effect due to the interblade vortex-phasing phenomena plays an important role in the lead-lag stability of multibladed hingeless rotors in hover.
Aeroelastic analysis of multibladed hingeless rotors in hover
Aeroelastische Analyse von mehrblättrigen gelenklosen Hubschrauber-Rotoren im Schwebeflug
AIAA Journal ; 33 , 12 ; 2348-2353
1995
6 Seiten, 12 Bilder, 25 Quellen
Article (Journal)
English
Hubschrauber , Rotor (Drehflügel) , Aerodynamik , Elastizität , Schweben , mathematisches Modell , Torsion , Wirbelströmung , Wirbelstraße , geometrische Form , dynamisches Verhalten , Druckkraft , Störungsfall , Prognose , Bewegungsgleichung , Finite-Elemente-Methode , Balken , Verlagerung , Vektor , Nichtlinearität , Durchbiegung , Systemvergleich , Gleichgewicht , Stabilität , Schwingungsdämpfung
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