Fluid-structure Interaction Effects on Free Vibration of a Vertical Rectangular Lock Gate using a near Truncated Boundary

摘要

In this paper, the change in natural frequencies of a lock gate structure is studied due to the fluid structure interaction effects between the gate and the reservoir using a near truncated far boundary. First of all, a relation is developed between the pressure and its gradient in the fluid, so that the far boundary of the fluid domain considered for analysis may be placed at a short distance from the gate structure. A three dimensional finite element method (FEM) with this far boundary condition is adopted for the evaluation of the dynamic pressure on the fluid-structure interface. A coupled relation is developed from the equation of dynamic pressure and the dynamic equilibrium equation of the gate to obtain the modified eigenfrequencies of the gate due to its interaction with the reservoir. The fluid is assumed to be inviscid, but compressibility effects without change in density are taken into account. The effects of free surface waves and hydrostatic pressure of the fluid are neglected in the analysis. The possible closeness of the far boundary from the gate structure and influences of the thickness and aspect ratio of the gate wall on eigenfrequencies are investigated.