Rich Dynamic Behaviors of Self-excited Oscillation of Collapsible Channel
ORAL
Abstract
Fluid-structure interaction (FSI) in collapsible channel flow is numerically studied with an immersed boundary-lattice Boltzmann method. Compared with previous studies, current method is able to simulate nonlinear fully coupled FSI in two-sided collapsible channel and high Reynolds numbers flow (Re up to 2000). The stability of the hydrodynamic flow and collapsible channel walls are examined for a wide range of Reynolds numbers, structure-to-fluid mass ratio, external pressure and wall thickness. Based on the numerical simulations, we (i) explore the physical mechanisms responsible for the onset of self-excited oscillations, and (ii) characterise the chaotic behavior of the collapsible channel walls. Rich dynamic behaviors of self-excited oscillation are observed. Regarding point (i), we identify that the flow bifurcate to bistable mode at Re=320 due to the symmetry breaking as the increase of Reynolds number. Besides, the external pressure applied on the elastic beams plays an important role in triggering the self-excited oscillation of the beam. And then for point (ii), the existence of chaotic behavior of the collapsible channel walls is confirmed by a very positive dominant Lyapunove exponent and the chaotic attractor in the velocity-displacement phase portrait.
*Qiuxiang acknowledges the support of the University International Postgraduate Award by the University of New South Wales. The computation work of this research was partially performed on the National Computational Infrastructure supported by Australian Government.
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