Author(s)

Z. G. Liu, Y. Liu & J. Lu

Abstract

The fluid-structure interaction for an elastic cylinder in an axial flow was studied numerically with the ALE method and the LES turbulence model. The commercial CFD software Fluent is used as the fluid solver and the Euler- Bernoulli beam solver is embedded into Fluent by its user defined functions (UDF). Two types of cylinder are included in this study. The motion for the first type of cylinder is constrained in one lateral direction and for the second in two lateral directions. The two types of cylinder are both released from their equilibrium state. When the stiffness is kept large enough, only weak oscillatory is induced by the flow. However, the motion of the cylinder induced by the flow may become unstable in the form of either buckling or oscillatory, when the stiffness becomes small enough. In this study, it is found that with the same simulation parameters the first type of cylinder is buckled and the second has an oscillatory. When buckled, the cylinder is located at a new state with weak oscillatory. The oscillatory after the instability has much larger amplitude than that before the instability. Keywords: CFD, fluid-structure interaction, fluidelastic instability, buckling, flutter. 1 Introduction One of the most classical subjects in fluid mechanics is the flow over cylinder, by which many interesting and significant phenomena are discovered such as Karman vortex streets [1] and also by which, for example, one can get the Kutta- Joukowski theorem, one of the most basic theorems in aerodynamics [2].

Keywords

CFD, fluid-structure interaction, fluidelastic instability, buckling, flutter.