Mode transition of a coupled rigid–flexible system in a uniform flow

The interaction between a rigid–flexible system and ambient fluid was simulated numerically at Re = 300 by the immersed boundary method. consists of stationary rigid plate upstream closed flexible filament downstream. For different lengths, four typical regimes for motions were observed. As length increases, successively experiences plate-like (P) mode, cylinder-like (C) slender-shape (S) mode finally enters wriggling (W) mode. It demonstrated frequency spectra that when increases up to critical value, second harmonic becomes dominant, corresponding transition from S W point, drag exerted on minimum. occurrence S–W found be caused increased inertia filament.