A method based on computational fluid dynamics (CFD) was developed to predict the unsteady aerodynamic characteristics. The computational method includes numerous techniques such as momentum source model

preconditioning method

unstructured overset grids and Spalart-Allmaras (S-A) turbulence model. The effectiveness of the computational method in simulating dynamic flow field of dual rotor micro air vehicle was validated by calculating hovering Caradonna-Tung rotor and pitching NACA0012 airfoil. The dynamic flow field of dual rotor micro air vehicle was numerically simulated; the hysteresis curve of unsteady aerodynamic coefficient was calculated and the effects of reduced frequency

forward speed and propeller speed on unsteady aerodynamic characteristics were analyzed. The computational results show that the hysteresis effect of moment coefficient increases as induced frequency

forward speed and propeller speed increase

and the hysteresis effect of lift coefficient increases as induced frequency and forward speed increase

however

the hysteresis effect of lift coefficient changes slightly as the propeller speed changes.