The aerodynamic performance of a 2D lumped flexible airfoil in forward flight

Abstract

The aerodynamic performance of a 2D lumped flexible airfoil in forward flight is studied by solving the incompressible N-S equations coupled with a structural dynamics equation for the motion of the airfoil. A lumped torsional NACA0012 airfoil in forward flight is employed and the flow field, the aerodynamic force, the energy efficiency, and the lumped torsional positions of the airfoil with different flexibilities are investigated. It is found that the flexibility influences the aerodynamic characteristics of the airfoil greatly and if the airfoil has an appropriate flexibility the flexibility can increase the thrust force and the energy efficiency while the mean lift force is almost unchanged. The results also show that a light airfoil possesses a larger propulsive efficiency than a heavy airfoil, and if the lumped torsional position is close enough to the leading edge of the airfoil the shedding of leading edge vortex can be delayed, which results in a greater thrust force.

Aerodynamic Performance of the Three-Dimensional Lumped Flexibility Bionic Hovering Wing

“…However, they drop sharply when f * crosses over 1.00 and even a negative value is observed, which indicates that the hovering performance is deteriorated. This conclusion is different with the results obtained in our previous 2D lumped flexible wing study [27], at which we concluded that the best performance of the wing is achieved when the wing with frequency ratio f * is close to but less than 1.00.…”