두 반전된 깃발의 균일 유동 내에서의 자가 진동 패턴 연구

Flutter instability has been studied to understand flapping patterns about thin plates or sheets. An inverted flag whose trailing edge is clamped in a uniform flow was known to alter its dynamics dramatically at a critical free-stream velocity. In this study, we investigated the interaction of two inverted flags whose fixed ends are symmetrically placed with respected to the vertical middle line of the flow zone. We examined flapping patterns of the two inverted flags by varying the relative gap between the two flags and aspect ratio of the flags. Our results show that the aspect ratio and the gap alter there critical free-stream velocity at which flutter instability occurs. Also we found several flapping modes : in phase flapping mode, out of phase flapping mode, attached mode, depending on there aspect ratio and a gap between them.