A NAVIER-STOKES/FULL POTENTIAL/FREE WAKE METHOD FOR ADVANCING MULTI-BLADED ROTORS

A hybrid scheme for predicting threedimensional unsteady viscous flows over isolated helicopter rotors in hover and in forward flight is introduced. The flow field is viewed in three parts; i) an inner zone surrounding each blade where wake and viscous effects are captured, ii) an outer zone away from the blades, and iii) a Lagrangean wake that lies inside the outer zone and beneath it, and induces wake effects to the outer zone. This technique is coded in a flow solver and validated through a study of hovering and advancing rotors.