Numerical study of flapping wing/tail aerodynamic interaction for flapping wing micro air vehicle

Taking the two-dimensional rigid flapping wing micro air vehicles model as research object, the aerodynamic characteristics of both single wing and tandem wing configurations were numerically evaluated. The numerical analysis methodology was transient and based on the dynamic grid technology. Simulation was conducted on the influence of reduced frequency of tandem wing, flapping wing to tail dimensionless horizontal distance and angle of attack on the aerodynamic performance. Results show that: (1) The tail of tandem wing is beneficial to the overall aerodynamic performance. Compared with the single wing configuration, the thrust coefficient and propulsive efficiency of tandem wing configuration are increased by 28.7% and 5.7% when the flapping wing to tail dimensionless horizontal distance is half of the wing length, respectively. (2) Reduced frequency is the key parameter that significantly influences the thrust. The higher reduced frequency strengthens the vortex-shedding and then results in an increase in thrust coefficient. The propulsive efficiency of single and tandem wings approaches maximal value when reduced frequency is about 1.0. (3) For the tandem wing configuration, the propulsive efficiency is optimized when the wing to tail flapping dimensionless horizontal distance is 1.1. (4) As the angle of attack increases from 0 degree to 20 degree, the lift coefficient increases and the thrust coefficient decreases. The flapping wing of the two configuration is predominated by drag at the moment angle of attack being 9 degree.