Study Of Flow-induced Vibration Of Radial Gate

Radial gates are widely used on dams and sluices. It is of practical and theoretical significance to analyze and evaluate the flow-induced vibration of the radial gate with hydraulic experiment and numerical computation.In the thesis, the theory of the flow-induced vibration of the radial gate is presented. And the flow fluctuating pressure acting on the gate is surveyed with hydraulic experiment. With the ANSYS and BEM program, the numerical model of the gate is established, and the gate structure's dynamic characteristic is analyzed. At last, the dynamic response of the Shifosi Radial Gate is computed and evaluated when the gate works at partial opening.The flow-induced vibration of the gate is fluid-structure coupling motion. The equation of the motion is difficult to solve. To obtain the approximate solution, the pressure acting on the gate is divided into two parts, one is the fluctuating pressure of the flow underneath the stationary gate, which is investigated with experiment; the other is the hydrodynamic pressure due to the vibration, which is equivalent to the attached mass matrix, damping matrix and stiffness matrix of the equation.In the hydraulic model experiment, with a homemade device, the pressure acting on an area is obtained from the pressure on a point. The fluctuating pressures acting on the different parts of the gate are measured simultaneously with DJ800. The distribution of the pressure in time and frequency domain is discussed, and the pressure is applied as the load in the subsequent FEM analysis.With the powerful software ANSYS, the FEM model of the gate is developed. The hydrodynamic pressure due to the coupled vibration is studied with Boundary Element Method, and the simplified formula for the attached mass matrix is derived. In the modal analysis, the natural frequencies of the gate in the water, as well as in the air, are calculated, and the modes are directly observed. In addition, principle of the optimization design is proposed.Finally, the vibration of the Shifosi Radial Gate is calculated, by performing the transient analysis with ANSYS. And the dynamic response of the gate, the displacement and the stress of the structure, is discussed. Adopting the first-passage failure mechanism, the dynamic reliabilities of the gate at different discharge positions are assessed.