Abstract
In this paper, we investigated the development of a vortex structure (horseshoe vortex and coherent vortex) around a vegetated groyne. Four groyne types (impermeable groyne (P=0) and the vegetated groynes(P=0.256∼0.512)) were used. For vegetated groynes, the vegetation on the weir crest was modeled by using circular cylinders. The results showed that (i) the horseshoe vortex is formed in front of the groyne, (ii) the horseshoe vortex is heterogeneous in the spaniwise ditrection and the downward flow occurs in Main-channel (iii) The spanwise vortex is generated behind the vegetated groyne and the flow separation length depends on the spanwise vortex strength.
