Study of flow characteristics around row of oscillating water column pile under regular waves

A numerical wave tank was developed based on Reynolds-Averaged Navier-Stokes equations with k−ω turbulence closure. The accuracy of numerical model was first verified by laboratory experiments. Then, the model was used to simulate the flow field characteristics near the device under the effect of regular waves. The vortex characteristics and its implication to local erosion mechanism were analyzed. Results show that under tested conditions, a concave horseshoe vortex is formed at the toe of the oscillating water column pile and wake vortices are formed around the structure. The strength of the horseshoe vortices decreases with the increase of the Keulegan-Carpenter (KC) number, and the strength of the wake vortices increases with the increase of the KC number. The horseshoe vortices are too weak to be the main factor in sediment scour at the range of KC number in this simulation, while the strong wake vortices are likely to be a main control factor of sediment initiation of motion, transport and scour near the pile foundation. © 2021, Zhejiang University Press. All right reserved.