Numerical investigation of submerged flexible vegetation dynamics and wave attenuation under combined waves and following currents

Wave attenuation by flexible vegetation is an increasingly significant research area in coastal and ocean engi-neering. Given the numerical research on flexible vegetation along with the combined waves and currents conditions have received insufficient emphasis, this study seeks to extend the application range of established numerical models to conditions with combined waves and currents, and further quantitatively reveal the effects of colinear following currents on submerged flexible vegetation dynamics and wave attenuation. By comparing with measurement data obtained from previous experimental studies, the reliability of the applied numerical methods in simulating flexible vegetation motions and wave attenuation under combined waves and following currents is confirmed. Scenario simulations illustrate that the Keulegan-Carpenter number and velocity ratio exert substantial nonmonotonic effects on the maximum horizontal force, stem tip excursion, and maximum horizontal stem tip displacement of flexible vegetation. And the presence of the following currents can both enhance and suppress the wave attenuation by flexible vegetation depending on the velocity ratio and water depth. Disparate regularities are revealed as the velocity ratio is higher or less than 3. This investigation can broaden the application of the flexible vegetation model and further advance the understanding of wave attenuation by flexible vegetation.