Assessment of Numerical Methods for Plunging Breaking Wave Predictions

Abstract

This study evaluates the capability of Navier–Stokes solvers in predicting forward and backward plunging breaking, including assessment of the effect of grid resolution, turbulence model, and VoF, CLSVoF interface models on predictions. For this purpose, 2D simulations are performed for four test cases: dam break, solitary wave run up on a slope, flow over a submerged bump, and solitary wave over a submerged rectangular obstacle. Plunging wave breaking involves high wave crest, plunger formation, and splash up, followed by second plunger, and chaotic water motions. Coarser grids reasonably predict the wave breaking features, but finer grids are required for accurate prediction of the splash up events. However, instabilities are triggered at the air–water interface (primarily for the air flow) on very fine grids, which induces surface peel-off or kinks and roll-up of the plunger tips. Reynolds averaged Navier–Stokes (RANS) turbulence models result in high eddy-viscosity in the air–water region which decays the fluid momentum and adversely affects the predictions. Both VoF and CLSVoF methods predict the large-scale plunging breaking characteristics well; however, they vary in the prediction of the finer details. The CLSVoF solver predicts the splash-up event and secondary plunger better than the VoF solver; however, the latter predicts the plunger shape better than the former for the solitary wave run-up on a slope case.

Numerical Study on Interfacial Structure and Mixing Characteristics in Converter Based on CLSVOF Method

“…Moreover, its application range is continually expanding. The research on this method is still limited to classic cases such as sloshing [26], friction stirring [27] wave breaking [28], dam break [29], bubble lifting in liquid [30], and spray [31] (droplet) wall collision phenomena. However, this approach is very limited in the study of gas-liquid two-phase flow in converters.…”

Hydrodynamic Modelling of Offshore Renewables: Experimental Benchmark Datasets and Numerical Simulation

“…Today, most of the two-phase CFD codes used for engineering purposes employ interface capturing methods with advection of a scalar field that represents the free surface such as the distance to the free surface in Level-Set methods or a volume fraction of water in Volume of Fluid (VoF) methods (Bhushan et al, 2021;. Within the topic of complex wave transformation including wave-breaking, the VoFbased, incompressible interFoam solver under the open-source framework OpenFOAM is a highly popular and commonly used to solve the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations with closure from a turbulence model as in, e.g., , Higuera et al (2013), , Stagonas et al (2018), andTorres-Freyermuth et al (2007).…”

“…Up till now, only CFD methods of Eulerian nature have been introduced. However, the Lagrangian method of Smoothed Particle Hydrodynamics (SPH) has grown increasingly popular in the past decade for especially large surface deformation cases within coastal engineering (Bhushan et al, 2021). The SPH method discretises the fluid domain into a set of fully Lagrangian computational grids or so-called particles.…”