| 講演内容 |
Micro UAVs are used under various circumstances nowadays. Their bodies are often made in light weight and processible materials such as plastics. These bodies can be morphed and vibrated easily by aerodynamic forces because of low rigidity. These actions also affect aerodynamic forces. In this study, modification to aerodynamic characteristics by morphing and vibration of planar wings with various Young’s modulus are investigated experimentally as well as flow fields around the wings. Motions of wings are obtained with a high-speed camera. Flows around the wings are evaluated with phase locked PIV technique. As a result, bending vibration of the wings is observed almost all over the angels of attack and twisting one being around the angles giving maximum lift force. Larger aerodynamic forces and delay in the stall are given under the condition that the twisting vibration occurs. Analysis of high-speed movies shows that amplitude of the twisting determines magnitude of variations in aerodynamic forces. The flow field observations indicate that the twisting vibration generates vortices near the trailing edge and they induce a flow toward upper surface of the wing. It reduces the volume of the separation bubbles on the wings, in particular, around center of the wing span. |
