Tsunami-like Flow-Induced Forces on the Landward Structure behind a Vertical Seawall with and without Recurve Using OpenFOAM

Abstract

It is more common to introduce the parapet/recurve/wave return wall over the existing structure, such as a vertical seawall or composite structure, to reduce the overtopping efficiently. The advantage of a recurve wall on top of the sea wall has been studied in the past in regards to wave interaction and overtopping. However, their efficiency in protecting the inland structure during extreme events such as flooding during a tsunami is unexplored. The present study addresses the effect of a vertical seawall with recurve in reducing the dam break surge simulating tsunami-induced forces on an inland structure. The study compares the momentum transferred on the landward structure behind a Vertical seaWall (VW) and a vertical wall with the Large ReCurve on the top (LRC) during overtopped conditions. The outcome from the numerical simulation shows an insignificant contribution due to the LRC in reducing the force on the inland structure compared to the VW, albeit delaying the impact time. However, the LRC performed slightly better in the case of a low-rise wall located near the inland structure than the VW. Furthermore, a low-rise VW increases the force and overturning moment on the inland structure compared to no-wall conditions. Both the LRC and the VW reduced the horizontal force on the structure linearly with the increase in height. An exponential decrease in the overturning moment was observed on the landward structure with the increase in the height of the VW or the LRC. Design equations are proposed for the forces and overturning moment reduction based on the height of the VW or the LRC.

Keywords

• tsunami mitigation
• vertical wall with recurve
• vertical seawall
• tsunami forces