Modeling of the fluid-induced vibrations in sliding gate dams

Prevention of damage to an elastic structure, such as the vibration of floodgate, requires serious consideration in the design. Hydrodynamic load characteristics and structural response under flow-induced vibration are mainly influenced by inertia, damping and elastic, geometric characteristics and hydraulic parameters. The purpose of this study is to investigate the dynamic behavior of sliding dam gates in the response to stimulation caused by fluid flow. The main drawback of the analytical models presented in the vibration dam gates is that, they supposed it as a linear system and non-linear behavior of the gates feedback are not considered in the in force calculations. Physical model of the gate in reality, is a self-excited model. So, expression of the force applied to the fluid by adding a harmonic excitation system is incompatible with the physical reality. If the non-linear behavior of the fluid pressure variation considered, vibration dam gate analytical models should be considered as a periodic models to analysis of the vibrational behavior. The qualitative analysis of the problem can be well approximated by the force, which should be able to establish the gate oscillatory behavior. In this paper, at first a nonlinear self-excited mathematical model for the fluid flow induced vibration, in sliding gate dam is presented. This model is based on assumptions that obtained by qualitative analysis of vibration dam gates experimental results. Results show that proposed model can produce permanent and self-stimulated vibration behavior. Then in the next stage the dynamic behavior of sliding dam valves, in response to flow excitation studies in ANSYS. Finally, to achieve the optimal valve geometry, numerical results for various shapes of valves are compared with experimental data