Study on a similar-flapping wing ornithopter and flow-field characteristic of blades

ZHANG Yu-hua1， DAI Qiang2， ZHOU Jin1
（1. College of Mechanical Engineering， Anhui University of Technology， Maanshan 243032， China；
2. Shantui Construction Machinery Co.，Ltd.， Jining 272000， China）

Abstract： In order to simplify the construction and motion control of the flapping wing mechanism，a new similar-flapping wing ornithopter was designed based on the half-rotating mechanism and inner cam with rotational follower. Its construction and blade motion principle were analyzed. A blade-fluid FE model was established using Fluent software. Changes of flow field characteristic around the two blades were discovered after the simulation analysis of the flow field with double blades in motion. The results indicate that the fluid velocity and pressure around the blades and the lift coefficient of a blade change with the position and orientation of the blades within a motional period，and are mutually affected by the movement of two blades，and the lift coefficient of a blade in former half of the period is greater than in latter half of the period，and the increase in the size of blade can effectively raise the lift coefficient. These provide practicable approaches for the lift calculation and offer important guidance to modify the lift calculation model of the similar ornithopter.
Key words： similar-flapping wing ornithopter； half-rotating mechanism； simulation analysis； flow field characteristic