Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Breaking waves interactions with vertical seawall attached with recurved parapet using the threedimensional parallel CIP-based model
Kaiyuan Zheng1, Xizeng Zhao1,*
1 Ocean College, Zhejiang University, Zhoushan, Zhejiang, China(2004). They provided general guidance for the design of the recurved
parapet. The effect of the overhang length of a recurved seawall inreducing wave overtopping was investigated by Swart (2016). With theincrease of overhang length, the decrease of overtopping volume willreach a certain extent, and then the longer overhang length has nofurther significance. The 2-D numerical simulations about non-breaking
waves on a vertical breakwater with a recurved parapet wall werecarried out by Castellino et al. (2018). They discussed the influence ofgeometry on the parapet for the impulsive pressure force. Ravindar andSriram (2021) discussed the variations of impact force on the overallstructure with different parapet types. These papers have all made many
contributions to the study of this issue. However, there is still a lot of
research that needs to be done there, such as accurate prediction ofslamming loads and evaluation of flow field characteristics aroundvertical seawall attached with recurved parapet and so on. In theprocess of wave slamming, three-dimensional bubbles will be formed,
and the fluid will move violently in space. The two-dimensional model
simplifies this process and can not accurately predict the impact
pressure. Therefore, in order to more truly simulate the slamming
process, an effective three-dimensional viscous flow model is necessary(Song et al, 2022).

ABSTRACT
Breaking waves interactions with vertical seawall attached withrecurved parapet is investigated by a three-dimensional parallel CIPbased model, which is accelerated by high-performance computing
based on Message Passing Interface algorithm and Open MultiProcessing algorithm. The Navier-Stokes equations are solved by theprojection method. A constrained profile (CIP) method is applied forthe convection term. The tangent of hyperbola for interface capturingwith slope weighting (THINC/SW) method is used to simulate thevariation of the free surface. Numerical results based on the parallel
CIP-based model are compared with the experimental results with goodagreements. The wave impact pressures on the vertical seawall attachedwith recurved parapet are accurately predicted. Besides, the large
deformation of the free surface, especially the wave profiles of thetransient wave impact process, is finely simulated. Three-dimensional
numerical investigation can help us better assess the reliability andsurvivability of these structures in presence of extreme loads.

KEYWORDS: CIP method; Wave and Structure Interaction; Parallelalgorithm; Recurved parapets

The purpose of this paper is to verify the reliability of the present
model for breaking waves impact on the vertical seawall attached withrecurved parapet. First, for the computational efficiency of the threedimensional problems, the present model will build the threedimensional CPU-accelerated framework to improve computationalefficiency. Second, the present three-dimensional multiphase flow
model will be used to simulate breaking waves impact on the verticalseawall attached with recurved parapet. The reliability of the model isdemonstrated by quantitative comparison with experimental data.
Finally, the safety assessment of the structure and hydrodynamic
characteristics will be analyzed. In fact, the present three-dimensionalmodel can help us understand the complex wave slamming process
more intuitively.

INTRODUCTION
As the global climate warms and sea levels continue to rise, it is very
important to reduce the damage of overtopping and slamming load tothe vertical seawall in extreme events. A sea-facing overhang structure,
the so-called recurved parapet, can be attached to a new or existingvertical seawall. The overhang structure, which forces the upwardrushing water and towering waves to curl toward the sea, can release
the energy of the waves back into the sea again and reduce the damage
to the structure. This process involves problems such as wave breaking,air trapping and wave slamming (Ravindar et al, 2019). How toaccurately predict the impact load and wave climb is a huge challenge,
both for the effectiveness of numerical models and the accuracy ofphysical experiments.

The full paper is arranged as follows: governing equations and thethree-dimensional CPU-accelerated framework will be introduced in
the section of the model. The benchmark of the impact of the breaking
waves on the vertical seawall attached with a recurved parapet will be
used to verify and validate the reliability of the present threedimensional parallel CIP-based model in the section of model

The influence of parapets and recurves on wave overtopping and wave
loading of complex vertical walls were studied by Kortenhaus et al.

1999