Flapping dynamics of an inverted flag

摘要: The dynamics of an inverted flag are investigated experimentally in order to find the conditions under which self-excited flapping can occur. In contrast a typical with fixed leading edge and free trailing edge, our study has edge. behaviour be classified into three regimes based on its non-dimensional bending stiffness scaled by flow velocity length. Two quasi-steady regimes, straight mode fully deflected mode, observed, limit-cycle large amplitude appears between two regimes. Bistable states found both transition transition. effect mass ratio, relative magnitude inertia fluid inertia, range for is negligible, unlike instability flag. Because unsteady force, sheet produce elastic strain energy several times larger than deformed improving conversion kinetic energy. According analysis leading-edge vortex formation process, time scale optimal correlates efficient during bending.