Further investigation on the resonance of free-surface waves provoked by floodgate maneuvers: Negative surge waves

In this paper, the resonance of free-surface waves was further investigated by considering the negative-surge particular framework. The 1-D Boussinesq model was used to describe the flow behavior, along with the (2-4)-dissipative scheme implemented for the numerical computations. The numerical model was validated against experimental data and alternative numerical solutions from the literature. The resonant frequencies of free-surface waves were firstly inspected and analyzed through analogy with the waterhammer phenomenon in pressurized pipe flows. Secondly, different critical scenarios governing depth oscillations were revealed and discussed, along with the use of the wave superposition approach as being a more realistic description of the free-surface waves distortion. Results revealated that the negative-surge wave mechanism exhibited severe behaviors which could critically affect the canal traffic and enhance the channel flooding risk, since they may entail both a hydraulic drop and a hydraulic bore with a magnitude that can exceed the value of the initial free-surface elevation.