Simulation Of Flow-induced Vibration Of Elastic Plates With Large Deformation Subjected To Axial Flow

The problem of plate and shell structures vibrating and losing stability under the effect of flow are common encountered and in urgent need of solving. In this paper, the fluid-structure coupling system of cantilevered elastic-thin plate with large deformation in axial flow is numerically simulated, the two-dimensional structures use ideal elastic material, the fluid domain adopt two-dimensional incompressible viscous flow, the method of two-way fluid-structure interaction is used combining with moving mesh technology, the strongly nonlinearity function of FSI in the finite element software ADINA are applied, and the results of numerical simulation are analyzed combined with the existing theoretical research results, in order to provide reference for the flow-induced vibration, prediction and control lose stability of this kind structure applied in practical engineering. Following are the main contents and results this study:1. The numerical simulation model of a single cantilevered elastic plate in axial flow is established, the characteristics of structure and fluid domain among the fluid-structure interaction system is analyzed under given different velocity. On one hand, the system loses stretched-straight balance state at a critical flow velocity by a Hopf bifurcation, leading to limit-cycle oscillations. By analyzing the time trace curves and the vibration responses, when flow velocity is less than the critical flow velocity, the plate keeps stable after a certain time; When flow velocity exceeds the critical flow velocity, the stable limit-cycle oscillations occurs, and with flow velocity increasing, the deflection and the plate’s frequency are both increasing, the time to reach the limit-cycle oscillations decreases, the plate vibration has a traveling wave feature. On the other hand, under given different flow velocity conditions, the flow domain is analyzed qualitatively by the cloud diagram of vorticity. Due to the influence of the plate vibration, karman vortex street occurs at the downstream. By comparing the vorticity, pressure and velocity at given flow velocity, the fluid and structure interaction system is explained vividly.2. The numerical simulation model of two parallel cantilevered elastic plate in axial flow is established, the characteristics of structure and fluid domain among the fluid-structure interaction system is analyzed under given different distance of parallel plates. The results are shown as follow: three different limit-cycle oscillations modes are found with the different distance between the two plates: in-phase oscillation, out-of-phase oscillation, and indefinite oscillation; the plate boundary layer shed from its free end and the wake are obtained under the in-phase and out-of-phase modes respectively; in addition, the two plates’ static displacement symmetrical and reverse direction are occurred under a given flow without applying the initial disturbance, and decreases with the distance increasing; it is found that the two plates show beating effect in the transition from in-phase mode to out-of-phase mode.