Numerical simulations of surf zone wave dynamics using Smoothed Particle Hydrodynamics

Abstract

In this study we investigated the capabilities of the mesh-free, Lagrangian particle method (Smoothed Particle Hydrodynamics, SPH) to simulate the detailed hydrodynamic processes generated by both spilling and plunging breaking waves within the surf zone. The weaklycompressible SPH code DualSPHysics was applied to simulate wave breaking over two distinct bathymetric profiles (a plane beach and fringing reef) and compared to experimental flume measurements of waves, flows, and mean water levels. Despite the simulations spanning very different wave breaking conditions (including an extreme case with violently plunging waves on an effectively dry reef slope), the model was able to reproduce a wide range of relevant surf zone hydrodynamic processes using a fixed set of numerical parameters. This included accurate predictions of the nonlinear evolution of wave shapes (e.g., asymmetry and skewness properties), rates of wave dissipation within the surf zone, and wave setup distributions. By using this mesh-free approach, the model is able to resolve the critical crest region within the breaking waves, which provided robust predictions of the wave-induced mass fluxes within the surf zone responsible for undertow. Within this breaking crest region, the model results capture how the potential energy of the organized wave motion is initially converted to kinetic energy and then dissipated, which reproduces the distribution of wave forces responsible for wave setup generation across the surf zone. Overall, the results reveal how the mesh-free SPH approach can accurately reproduce the detailed wave breaking processes with comparable skill to state-of-the-art mesh-based Computational Fluid Dynamic models, and thus can be applied to provide valuable new physical insight into surf zone dynamics.

Non‐hydrostatic, Non‐linear Processes in the Surf Zone

“…This is explained by the working principle of resistive wave gauges whose response is proportional to the wire wet length. This cross comparison between measuring techniques near the breaking point underlines the importance to consistently compare the same quantities, whether the comparisons are made between different measuring techniques or between numerical models and experimental data (Lowe et al, ).…”

Validation of RANS Modelling for Wave Interactions with Sea Dikes on Shallow Foreshores Using a Large-Scale Experimental Dataset

“…However, it is acknowledged that some uncertainty remains regarding how resistive type wave gauges measure the free surface in the presence of air-water mixtures along the gauge. This could lead to discrepancies in the numerical-experimental model comparisons in the surf zone and on top of the promenade [72].…”

Stabilized RANS simulation of surf zone kinematics and boundary layer processes beneath large-scale plunging waves over a breaker bar

“…Christensen, 2006;Zhou et al, 2017) or a Smoothed Particle Hydrodynamics (SPH) approach (see e.g. Lowe et al, 2019) can potentially handle the breaking processes and boundary layer dynamics naturally. CFD simulations of breaking waves are still computationally demanding and it is often necessary to work with the least computationally demanding of the three CFD approaches, namely the RANS models.…”