Response of Venice storm gates to incident waves

Abstract

For the prevention of flooding of Venice a system of gates to close the inlets of the lagoon has been designed. Each system is composed of a series of 20 hollow gates hinged at the bottom. In the present work a linear theory is developed first to study the motions of the gates forced by a monochromatic incident wave. The gates are assumed to be vertical and the fluid domain is approximated to a channel of infinite length on the Adriatic side and to a semi infinite space on the lagoon side. Several theorems based on Green's formula are developed to get a deeper understanding of the physics of the problem and to check both the theory and the numerical computations performed. In particular, the law of energy conservation is derived. The amplitude of gates motion, added mass and radiation damping are reported for a large interval of periods. Synchronous resonance of the gates is found and the occurrence of negative added masses is reported and discussed.