Experimental Study on the Effect of Inertia Force on Aerodynamic Performance of Flapping Wings for Micro Vehicles
In the present study, the aerodynamic characteristics such as instantaneous lift and time-averaged lift of two flexible membranes (covered and uncovered) wings are compared in order to assess the effects of inertial force on the aerodynamic performance for flapping flight applications. The experiments are performed in an open circuit wind tunnel with of non-return airflow with a test section of (0.3m x 0.3m) and are capable of speeds from 0.5 to 30 m/s. The time-averaged lift as functions of flapping frequency, forward flight velocity, and the orientation angle of the flapping motions with respect to the incoming flows are measured by using a strain gauge balance and KYOWA PCD-300A sensor interface data acquisition system. It is found that the inertial forces are periodic with a frequency similar to that of the flapping motion (9Hz), and the estimated mean inertial forces at various frequencies (4Hz to 9Hz) of the wings are quite small, which is less than 7.2 % of the corresponding lift force. It is found the lift force, inertial and aerodynamic forces which increase with the flapping frequency.