Application of Leading-Edge Tubercles on Rotor Blades

Abstract

This study explores the effects of leading-edge tubercles applied to a canonical rotor blade in an effort to improve aerodynamic performance of a rotor in hover, without sacrificing forward flight performance. Various tubercle shapes and configurations were analyzed using computational fluid dynamic simulations using Euler and Reynolds-averaged Navier–Stoke equations. Improvements in figure of merit up to 3% were found over the baseline rotor for specific tubercle configurations when operating at pitch angles between 2 and 11 deg and tip Mach numbers between 0.6 and 0.83. An increase in thrust coefficients and reduction in power coefficients over the baseline rotor were both attributed to alteration of flow behavior in different regions of the rotor blade when leading-edge tubercles were applied.