Experimental study of local scour around inclined piles in combined waves and current

Abstract

Compared to vertical piles, the position relationship between the inclined pile and seabed has some extra effects on the surrounding wave-current interaction and sediment transporting mechanism. A series of local scour experiments with wave-current flume are conducted for investigating scour characteristics and influencing factors around inclined piles and vertical piles at a certain inclination angles range. The experimental results indicates that there are substantial differences in scouring variation patterns between upstream inclined piles, downstream inclined piles and vertical piles, and the suppression impact of pile inclination angle on scouring was closely related to the wave-current conditions. The magnitude relationship of relative scour depth (S/D) between the inclined and vertical piles will change visibly when the sand transporting capacity under wave-current action reaches a certain level. The obtained multiple regression equation based on mixing training datasets could provide reasonable estimation for scour depth around inclined and vertical piles under wave-current and only current action.