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

Turbulence effects on wave load acting on a curved sea wall
Xiao Hu, Shuling Chen
School of Naval Architecture and Ocean Engineering, Jiangsu University of Science and Technology
Zhenjiang,Jiangsu,China

ABSTRACT .

sufficient for reliable predictions.Therefore, solutions are sought bycomplete nonlinear simulations such as computational fluid dynamics(CFD).
Numerous numerical models and software have been developed basedon wide ranges of theoretical models, including the fully nonlinear
potential theory (FNPT) and the Navier-Stokes (NS) theories. The
FNPT can be solved by the boundary element method (e.g. Ning et al,2017), the finite element method (e.g. Wu & Hu, 2004), the quasiarbitrary Lagrange Euler finite element method (QALE-FEM, Yan andMa, 2007, 2010a; Ma and Yan, 2006, 2009), the spectral elementmethod (EngsigKarup et al, 2016), the high-order spectral method(Ducrozet et al, 2016) and the spectral boundary integral method(Wang & Ma, 2015; Wang et al 2018). The numerical methods forsolving the NS model exhibit more significant diversities comparedwith the FNPT models. One may categorise them into the conventional
mesh-based methods, e.g. the finite volume method (Hildebrandt, et al2014; Xie, 2012, 2013, 2015; Yang et al 2017), and the meshless(particle) methods, including the smoothed particle hydrodynamics(SPH, e.g. Lind, et al., 2012; Zheng, et al., 2014), the moving particle
semi-implicit method (MPS, e.g. Khayyer et al., 2019) and themeshless local Petrov-Galerkin method based on Rankine source
solution (MLPG-R, e.g. Rijas et al., 2019). Generally speaking, solving
the NS model is more time-consuming compared with solving theFNPT model, not only because of its higher degree of complexity of thegoverning equations but also due to its requirement on higher meshresolutions to achieve a convergent solution. This is confirmed by theCCP-WSI blind test using cases with a fixed FPSO subjected toextreme waves (Ransley, et al., 2019; Yan, Xie et al., 2019), whichconcluded that the accuracy of the FNPT models, such as the QALEFEM (Yan and Ma, 2007; Ma and Yan, 2009), is at a similar level as
the NS models but requires much less computational time (~ 10%).
However, the FNPT cannot resolve the viscous and turbulent effects,
which may be significant in many scenarios, e.g. when the structure
size is significantly smaller than the wave length and when wave
breaking occurs, due to its theoretical assumption that the fluid isinviscid, irrotational and incompressible. This drives the developmentsof hybrid approaches combining the FNPT (or other simplified models)with a NS model for robustly modelling the wave-structure interactions.
The fundamental idea of the hybrid approach is that the NS model isapplied to a small region, where small- and micro-scale physics, e.g.
the vortex shedding and flow separation, are significant; in otherregions,e.g. the wave propagation away from the structures, the FNPT
model are employed. Both the meshless (Sriram et al., 2014; Fourtakas
et al., 2017; Yan and Ma, 2017; Zhang et al 2020) and the mesh-based

In the coastal engineering, the prediction of wave load on a coastal wall
structure plays a crucial role for evaluating the reliability andsurvivability of the structure. This paper contributes to the multi-scalecomparative study conducted in the ISOPE 2022 regarding the regularwave impact on the sea wall, by using the commercial software STARCCM+, a two-phase flow with volume of fluid (VOF) technique will beused to model the water waves. After being validated using theexperimental data, a further investigation on the turbulent effect during
the violent wave impact will be carried out. In this investigation, thefluid is considered to be incompressible and different turbulencemodelling will be used.
KEY WORDS: Numerical simulation; CFD; wave impact.

INTRODUCTION
For survivability of the marine, coastal and offshore structures, theinteraction between extreme waves and structures needs to be reliably
predicted in engineering practices. As a typical structure, cylinders
have been widely used, e.g. as the foundation of oil/gas platform andoffshore wind turbines. Focusing waves, on the other hand, are widely
accepted to be a representative of the extreme waves in current
experimental and numerical researches. The interaction between thefocusing waves and the cylinder has attracted extensive studies recently(e.g. Hildebrandt et al 2014; Yan et al, 2015). Considering the fact thatthe extreme waves often involves a significant nonlinearity, the linear
and second order wave theories widely used in the routine design may
not be sufficient for a reliable prediction. Consequently, solutions by
the fully nonlinear simulations, e.g. the computational fluid dynamics(CFD), are sought for.
To ensure the viability of marine, coastal and offshore structures, theinteractions between extreme waves and structures are needed to bereliably predicted in engineering practice. Coastalbreakwaters and seawalls have been widely used in coastal areas as a typical coastalstructure.On the other hand, in the current experimental and numericalstudies, fragmentation waves are widely considered as the mostimportant cause of damage to coastal structures such as
breakwaters.The interaction between breaking waves and thebreakwater coast has recently attracted extensive research (e. g.,Mazinani et al., 2015; Hayatdavoodi et al., 2016).Given that extreme
waves often have significant nonlinearity, the linear and second-orderwave theories widely used in conventional designs may not be2678