EFFECT OF BLADE-TIP PLANFORM ON SHOCK-WAVE OF ADVANCING HELICOPTER BLADE

The effect of blade-tip planform on the behavior of shock waves on the advancing rotor blade was investigated in detail using a calculation method that solves three-dimensional Euler equations by an implicit fi nite difference method. The Newton iterative method was applied to obt ain the unsteady solution in forward night. The calculations were perf ormed for the blades having the NACA 0012 airfoil section along the en tire blade span to investigate the planform effect alone. The parametr ic study clarified the effect of the sweep and the taper on shock-wave generation. In addition, a guideline of the blade planform design for the advancing blade was suggested, and a newly devised tip planform t hat prevents shock-wave generation was proposed.