A Numerical Study of Rotor Blade Loading for Coaxial Rotors

With coaxial rotors receiving increased interest in commercial and aerospace industries, the need to better understand the underlying physical character of coaxial rotor is growing. Coaxial rotors drive an increase in the complexity of rotor interactions that involves coxial-rotorblade-vortex interaction (CR-BVI), turbulence, shedding, and downwash effects. Improving the understanding of these phenomena is demanded to establish better methodologies relevant to designing coaxial rotors. This paper intends to demonstrate relationships between rotor interactions and their resulting thrust profile and tip-loss location. The effort is based on a series of simulations from Computational Fluid Dynamics (CFD), where cases are evaluated and described with respect to CR-BVI. It is found that CR-BVI can drive the thrust profilea long lower rotor blades, which is a strong function of azimuth, RPM, and cruise velocity. Additionally, tip-loss locations are found to shift primarily due to advance ratio µ.