Numerical simulation of surf-zone turbulence beneath plunging breakers using Reynolds stress models

Abstract

This study applied Reynolds transport models (RSMs) to simulate turbulence under waves and plunging breakers. A simplified analysis that disregarded the diffusion effect on turbulence revealed a two-way energy transfer between waves and turbulence. Moreover, the Stokes drift was a crucial factor for enhancing the turbulence intensity, and the growth rate of the turbulence was directly proportional to the square of the wave steepness. Regarding plunging breakers, we observed that RSMs and the stabilised k−ω model yielded similar performances in simulating the free-surface displacement and velocity. However, in terms of turbulence intensity, RSMs demonstrated better accuracy. The differences in the pressure rate of strain tensor within the model formulae insignificantly affected the turbulence intensity beneath the plunging breakers.