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Based on the RANS equations and applying the waves2Foam solver in OpenFOAM, the study numerically investigated the turbulent kinetic energy (TKE) generated due to emergent rigid vegetation in water waves. The numerical results show that the TKE generated due to emergent vegetation in water waves increases with decreasing water depth and increasing wave height and period, as well as vegetation density and stem diameter. Moreover, compared to wave height, the influence of wave period on the stem-generated TKE in waves is more significant. Furthermore, the ratio of the amplitude of wave motion trajectory to stem spacing has a significant impact on the stem-generated TKE in waves. When the amplitude of wave motion trajectory is less than half of the stem spacing, the stem-generated TKE in waves is similar to the TKE of the bare bed in waves. In the case where the amplitude of wave motion trajectory is greater than half of the stem spacing, the stem-generated TKE in waves in the front of the vegetation will be significantly enhanced. Based on the study, an improved formula is proposed for predicting the stem-generated turbulence in waves. • Stem-generated turbulent kinetic energy in waves increases with decreasing water depth and increasing wave height and period. • Stem-generated turbulent kinetic energy in waves increases with increasing plant density and stem diameter. • Influence of the ratio of wave excursion to stem spacing on stem-generated TKE in waves. [ABSTRACT FROM AUTHOR]

This study provides a numerical model to investigate the influences of breakwater layout on coastal waves, wave-induced currents, sediment transport and beach morphological evolution in the vicinity of breakwater. The numerical model is developed based on the sub-models for nearshore wave, wave-induced current, sediment transport and beach morphological evolution. Nearshore wave is simulated based on the parabolic mild-slope equation considering wave refraction, diffraction and breaking effects. Wave-induced nearshore current is modeled using the nonlinear shallow water equations in which wave radiation stresses are provided by wave model for driving current. Then, the two-dimensional suspended sediment transport equation, bed-load equation and coast beach morphological evolution are coupled with the wave and current models for simulating sediment transport and morphological evolution in coastal waves and wave-induced currents. The numerical model is firstly tested by the experiment results for coastal waves, near-shore currents, sediment transport and beach morphological evolution around breakwater from the Large-scale Sediment Transport Facility at the US Army Corps of Engineer Research and Development Center ( Gravens and Wang, 2007 ). Then the model is used to study the influences of breakwater layout on coastal waves, wave-induced currents, sediment transport and beach morphological evolution by set several breakwater layouts in the LSTF basin. [ABSTRACT FROM AUTHOR]

The regular wave attenuation in following and opposing currents due to rigid, emergent vegetation has been studied by physical and numerical simulation in this study. Firstly, laboratory experiments were conducted to investigate the effect of currents on wave attenuation due to vegetation. Then, to overcome the limitation of the experimental conditions, a numerical model, based on the Boussinesq equations and validated by the experimental results, was applied to further investigate the effects of current velocity, vegetation density and water depth on wave attenuation due to vegetation in currents with larger α (the ratio of current velocity to the amplitude of the horizontal wave orbital velocity) range. The results show that both following and opposing currents can enhance or suppress wave attenuation due to vegetation depending on α. For the studied vegetation densities and water depths, the effect of wave attenuation due to vegetation in currents first decreases and then increases with the increase of α. Moreover, wave attenuation due to vegetation in currents is increased with the increase of vegetation density and decreased with the increase of water depth, and both of them have no influence on the relationship between relative wave height decay and α. • Wave attenuation in following and opposing currents due to rigid vegetation. • Influences of current direction and velocity on wave attenuation due to vegetation. • Influences of vegetation density and water depth on wave attenuation by vegetation in currents. [ABSTRACT FROM AUTHOR]