Resonance of Free-Surface Waves Provoked by Floodgate Maneuvers

Prediction of damage caused by floodgate maneuvers is treated by the determination of factors amplifying the magnitude of generated damage. The identification of vulnerable areas is obtained by analogy with the water-hammer phenomenon in pressurized pipes. The numerical model is based on the Boussinesq assumption for transient flow in open channels and solved by the Mac-Cormack scheme. Transient flow concerns a rectangular channel where the initial steady state is uniform. Transient regime is provoked by the movement of a floodgate at the upstream extremity of the channel producing sinusoidal fluctuations of depth. A condition of floodgate closure is imposed at the downstream extremity. The applied excitation has permitted analysis of the fluid structure interaction, examination of pulsations provoking the resonance of the free-surface waves, and study of the evolution of depths according to time along the channel. According to the frequency of the movement of the floodgate at the upstream end, distortion of depth profiles or oscillations over these profiles may appear. The frequency value also has a significant effect on the flow depth evolution and can provoke the flooding of the channel.