Numerical Simulation of Flapping Airfoil Aerodynamic Characteristics

Flapping airfoil flight technology is widely used in defense and civilian fields, and huge economic benefits can be created. The bionic flapping airfoil is the research object of this paper. The influence of flapping frequency, flight trajectory, different airfoil types, and various flapping layouts on the aerodynamic characteristics of the flapping airfoil is investigated through numerical calculation. It is found that an increase in the flutter frequency can lead to an increase in the lift and drag of the flutter airfoil, as well as the strength of the flutter airfoil leading edge vortex, thereby improving the aerodynamic characteristics of the flutter airfoil, but the increase in the frequency leads to the decrease in the lifting efficiency. With the same symmetry of the trajectory of the flapping airfoil, the flapping airfoil lift characteristics are the same, but the drag characteristics may be different. If the symmetry of the flapping airfoil trajectory is distinct, the lift and drag characteristics of the flapping airfoil are different, and it is also found that the best lifting efficiency occurred in the “∞” trajectory. If the curvature and thickness of the airfoil are different, the aerodynamic characteristics of the flapping airfoil are distinct. Finally, the effect of different layouts on the aerodynamic characteristics of the flapping airfoil is examined. It is found that both tandem and parallel layout flapping airfoils can effectively increase the lift drag, but both tandem and parallel layout flapping airfoils lead to a decrease in the lifting efficiency.