Aerodynamic forces acting on an albatross flying above sea-waves

Numerical investigation on the dynamic mechanism has been made for an albatross to fly effectively near sea surface. Emphasizing on the effect of the sea wave, the albatross is simplified as a two-dimensional airfoil and the panel method based on the potential flow theory is employed to calculate the wave effect on the aerodynamic forces. The numerical results have been presented for the states of flying at different constant speeds with constant heights above sea level, and flying at different constant speeds with the combined oscillations of pitching and free heaving. It is shown that the albatross flight efficiency depends on not only the speed and height of flight but also the wave amplitude and the wavelength. The albatross benefits by wave effect to get thrust, so as to reduce the resistance in the circumstances of rough sea.