Experimental investigation of flapping mechanism of the black-headed gull in forward flight

Abstract

Many developments in aerospace science have originated from nature. One of these developments has been obtained through inspirations from flying locomotion. The aim of this study is to simulate the flapping mechanism of the black-headed gull in forward flight. The wing of the black-headed gull is characterized entirely by complex dihedral, dividing the wing into two distinct parts. Hence, a flapping mechanism with different bending deflection angles is constructed and compared with a primitive flapping mechanism. Firstly, parametric studies are conducted to assess the role of flapping frequency, velocity and bending deflection angle on the lift, thrust and power loading of the membrane flexible wing at 10 ° angle of attack. Secondly, dimensional analysis is used to establish the similarity between the real gull and the constructed mechanism. Superiority of the bending deflection mechanism is concluded in forward flight against simple flapping wing in terms of aerodynamic forces as well as power loading parameter. It is found that although the aerodynamic coefficients decrease with increase in advance ratio, the best power loading of the black-headed gull is obtained between advance ratio of 2 and 3, in the gull's aerodynamically quasi-steady regime.