Numerical investigation of damping effect and flow characteristics induced by rigid vegetation in current-wave flows.

In the paper, a 3-D numerical model based on the olaFlow solver to study the vegetation effects on flow characteristics and turbulent structure as well as wave attenuation under combined regular wave-unidirectional current conditions. The results show that following currents can either promote or suppress wave attenuation within the velocity magnitude specified in the paper, whereas opposing currents always enhance wave damping. Moreover, the emergent canopy and a staggered configuration resulted in increased wave-height attenuation. The time-averaged velocity patterns are various for submerged and emergent scenarios with different configurations. Furthermore, the time-averaged velocity magnitude inside the canopy decreases as the wave height increases for following flow conditions, while it increases in opposing currents. The time-averaged turbulent kinetic energy (TKE) inside the canopy follows the same distribution pattern as that of time-averaged velocity, and the maximum values of time-averaged TKE for the submerged and emergent canopies appear at the free surface, and above, respectively. The flow field characteristics show different patterns for various wave-current combinations and vegetation configurations, which provides a microscopic perspective to understand the interaction of vegetation-wave-current. • A three-dimensional numerical model using cyclic boundary based on the OlaFlow solver was developed. • Time-averaged velocity and turbulent kinetic energy within submerged/emergent canopy present different patterns. • Microscopic flow fields characteristic within the vegetation in following and opposing currents are presented. [ABSTRACT FROM AUTHOR]