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The effects of rigid emergent vegetation on wave overtopping have been studied by numerical simulation in this study. The numerical model is based on second-order fully nonlinear Boussinesq equations and solved by a combination of finite difference and finite volume methods. Physical laboratory results of wave propagation in the vegetated area and wave overtopping on a bare slope were used to validate the capability of the model, and the numerical and experimental results agreed well, which indicated that the model can well predict wave overtopping on a vegetated slope. Then, based on the model, the effects of rigid emergent vegetation on wave overtopping were investigated. The results showed that the wave overtopping volume decreases exponentially with the increase of vegetation volume per unit water volume V veg / V w , and the wave overtopping volume can be decreased by 50% when V veg / V w equals 0.01. • Influences of rigid emergent vegetation on regular wave overtopping. • Effects of plant diameter, vegetation density and volume on wave overtopping. • Effects of wave period and height on wave overtopping. [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]

Coastal vegetation is capable of reducing wave run-up and protecting coasts from flooding and land loss. This study numerically investigates the effect of width of emergent rigid vegetation on wave run-up attenuation. The numerical model is based on two-order fully nonlinear Boussinesq equations and solved using a combination of finite difference and finite volume methods. Physical laboratory data pertaining to long period wave run-up on a bare and emergent vegetated sloping beach is used to validate the accuracy of the model. Next, based on the model, the effect of vegetation zone width on wave run-up attenuation is investigated. The numerical results indicate that coastal vegetation can considerably decrease the wave height and wave run-up, and the wave run-up decreases monotonously with increase in the vegetation width. Moreover, the reduction rates of the wave height and wave run-up, caused by the vegetation zone, demonstrate an overall increasing trend with increase in the wave period when the ratio of vegetation zone width and wave length is constant. • Numerical simulation for coastal wave run-up on vegetated sloping beach. • Attenuation effects of vegetation on coastal wave run-up. • The effect of width of vegetation on wave run-up attenuation. [ABSTRACT FROM AUTHOR]