ON THE EFFECTIVENESS OF OSCILLATING WATER COLUMN DEVICES IN REDUCING THE AGITATION IN FRONT OF VERTICAL WALLS HARBOR STRUCTURES

Lorenzo Cappietti,Irene Simonetti

doi:10.9753/icce.v36.papers.112

Abstract

Reducing wave reflection at vertical wall harbor structures is an important goal to ease mooring and maneuvering inside the port area. In this study, numerical simulations have been carried out to assess the effectiveness of Oscillating Water Column devices as anti-reflective systems to be integrated in vertical wall harbor structures. The numerical simulations have been carried out in a Numerical Wave Tank, implemented in the Computational Fluid Dynamics environment OpenFOAMÂ®. A methodological approach to separate the reflected and the radiated wave components is presented. The interaction (destructive/constructive interference) between the reflected and the radiated wave field is studied. Furthermore, a preliminary assessment of the effect of basic design parameters of the Oscillating Water Column on the wave field in front of the structure is discussed. A relatively good performance of the device is found, with a minimum reflection coefficient of around 15%, suggesting that the device could efficiently be used to reduce wave agitation in front of vertical wall harbor structures.

Highlights

Wave reflection at harbor structures negatively affects the navigability of entrance canals and harbor tranquility
This paper aims to contribute to the present knowledge on the effectiveness of an Oscillating Water Column (OWC), embodied in quay walls or harbor breakwaters, as a way to reduce wave reflection at vertical wall structures
The possibility of using OWC devices to reduce the agitation in front of vertical wall harbor structures is investigated, with a particular focus on the global wave reflection and on the interaction among reflected and radiated fields

Summary

Introduction

Wave reflection at harbor structures negatively affects the navigability of entrance canals and harbor tranquility. In case of rubble-mound structures this phenomenon is relatively limited if compared to vertical-wall structures. For deep water applications, the use of the vertical-wall structures is an almost obliged choice due to economic reasons. Vertical wall structures are the preferred choice of harbor managers since they permit a better design of berthing structures and offer an effective approach for reducing the space occupied inside the harbor area, i.e. limiting the footprint of the mooring structure. Reducing the wave reflection at vertical wall structures is an important measure. Several low-reflectivity structures, to cope with this specific problem, have been presented in the literature, as reviewed in Oumeraci, 2010 and Huang et al, 2011

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