Multi-Fidelity Coupled Trim Analysis of a Flapping-Wing Micro Air Vehicle Flight

This study provides a methodology to analyze the performance of a millimeter-scale flapping-wing micro air vehicle in hover and steady forward flight. Using a flight dynamic model of the insect, which comes embedded with simplified quasi-steady wing aerodynamics and is coupled to high-fidelity computational fluid dynamics analysis, trim solutions are obtained in realistic time frames. This procedure is analogous to rotorcraft periodic coupling for trim. Six iterative coupling cycles are sufficient to obtain convergence in the wing loads and trim variables for the cases investigated. This multifidelity approach, where many quasi-steady calculations are combined with a judicious number of computational fluid dynamics simulations, maybe used in parametric sweeps and design studies to improve hover and cruise performance. The trim variables chosen in this study are the parameters used to describe the wing kinematics (stroke amplitude phi(max), stroke flapping bias phi(off), and stroke plane tilt beta). Flight conditions investigated are hover and three forward flight speeds. At hover, the wing kinematics parameters produce linearly independent force and moment components in the longitudinal plane. In forward flight, cross couplings manifest between the individual wing kinematics parameters and the longitudinal forces and moments. Thus, the one-to-one correlation between forces and individual controls that exists at hover is lost in forward flight.