Wenqing Yang

Dynamic Fluid-Structure Coupling Method of Flexible Flapping Wing for MAV

AbstractThis paper presents a numerical method to simulate the dynamic interaction between the structural deformation and the aerodynamic characteristics of flexible flapping wing for micro air vehicle (MAV). A fluid-structure coupling solver is developed based on the Navier-Stokes equations and the structural dynamic equations. In addition, the interface data exchange method based on the radial basis function and the moving mesh generation method based on the infinite interpolation are applied, which play an important role in the coupling research. The preceding method is validated by comparison with the wind tunnel experimental results. For the research scope of this article (R=5×104), the flexible deformation impacts of flapping wing on aerodynamic performance are presented. The simulation results proved that the structural deformation has a significant effect on the aerodynamic forces, especially on the thrust, and the structural deformation is determined by aerodynamic and inertial forces together, b...

Numerical Study of Flapping Wing Air Vehicle Based on Chimera Grid

A method is developed to investigate the aerodynamic characteristics of flapping wing air vehicle by solving the 3D Navier-Stokes equations based on the chimera grid. The spatial discretization is characterized by a second-order cell-center method for finite volumes. A five-stage Runge-Kutta scheme is employed to achieve convergence of the solution by integration with respect to time. For unsteady flows an implicit dual time-stepping scheme is used. Implicit residual smoothing is employed to accelerate convergence. The BaldwinLomax algebraic turbulent model is applied for calculating the turbulence flows. The grid system is based on the chimera grids which are composed of the motion wing grid and stationary background grid. The background grid includes fuselage, vertical and horizontal stabilizers. An efficient method, namely distance-decreasing searching method, is developed to apply on the hole-cutting and the interpolation cells searching of chimera grid preprocessing. Based on these numerical methods, the aerodynamic characteristics of flapping wing air vehicle can be researched. The numerical result shows that the flapping wing generates the main part of lift force and all the thrust force. The existence of fuselage can increase the drag force or decrease the thrust force. This solver can be used to investigate the layout of parts so it is practical in researching and designing of flapping wing air vehicle.

Dove: A biomimetic flapping-wing micro air vehicle:

This paper describes the design and development of the Dove, a flapping-wing micro air vehicle (FWMAV), which was developed in Northwestern Polytechnical University. FWMAVs have attracted international attentions since the past two decades. Since some achievements have been obtained, such as the capability of supporting an air vehicle to fly, our research goal was to design an FWMAV that has the ability to accomplish a task. Main investigations were presented in this paper, including the flexible wing design, the flapping mechanism design, and the on-board avionics development. The current Dove has a mass of 220 g, a wingspan of 50 cm, and the ability of operating fully autonomously, flying lasts half an hour, and transmitting live stabilized color video to a ground station over 4 km away.

Effect of wing flexibility on flight dynamics stability of flapping wing MAVs in forward flight

The paper presents a qualitative study of the effect of the wing flexibility on the flight stability of flapping wing micro air vehicles in forward flight. The longitudinal dynamic flight stability is compared between rigid wing flapping wing micro air vehicles and flexible-wing flapping wing micro air vehicles. The aerodynamics derivatives are computed respectively using the method of computational fluid dynamics and fluid–structure interaction method, and the techniques of eigenvalue and eigenvector analysis are applied to solve the equations of motion. It is shown that the flexibility can change the stability properties of the flapping micro air vehicles from unstable to stable. Besides, the position of mass center of flapping micro air vehicles is also a key factor to the flight stability, which provides a new insight to design a stable flapping wing micro air vehicle.