Numerical and Experimental Investigation of Dynamic Characteristics of the Bottom Outlet of Vaniar Dam

Dynamic characteristics of the service gate of Vaniar Dam are studied in this paper. Feature of pressure fluctuations induced by turbulence on the skin plate at different local openings is investigated, which is the basic dynamic load acting on the gate. The Fast Fourier Transform (FFT) algorithm is used to convert a digital signal in the time-domain into a set of points in the frequency-domain. Finite Element Method (FEM) is also used to analyze the free vibration characteristics of the gate at different openings. The paper presents a numerical procedure based on the finite element discretization that treats vibration analysis of the service gate. The natural frequencies obtained by FEM are compared with the frequencies of pressure fluctuations measured in the hydraulic model test of the outlet to investigate the avoidance of resonance phenomena at the gates. The mode shapes of the gate are also presented.Copyright © 2008 by ASME