Flow analysis of twin-rotor configurations by Navier-Stokes simulation

The flows of coaxial, tandem and side-by-side twin-rotor configurations are simulated numerically. The steady, incompressible Navier-Stokes equations with momentum source terms modeling the rotors are used for the flow simulations. The calculated rotor performance coefficients and wake geometries for coaxial rotors are in good agreement with available experimental and flight test data. By comparing the induced velocities, performance coefficients and general flow field of the twin-rotors to those of a single rotor, the aerodynamic interaction effects between the two rotors of each twin-rotor configuration are studied and revealed.