Study on the effect of internal reefs deflection on the flow field effect of unit reef

Artificial reef (AR) is generally utilized by the structure shape of unit reef (UR) in practical applications, and the UR construction part is the most important part to exert the flow field impact. However, there is currently limited scientific study on the effect of internal flow field effect inside the UR and lacks systematic theoretical basis. In this paper, the numerical simulation method was first verified by flume tank experiment with Particle Image Velocimetry (PIV) technology, and the results showed that numerical results were consistent with the experimental results. The numerical simulation method was then employed to assess the impact of the longitudinal interval on the flow field effect of three reef arrays, using the upwelling efficiency index as the evaluation standard. The study also investigated the influence of the deflection of individual reefs within the UR on the overall flow effect. The results indicate that the deflection of the reefs encountering the inflow initially had the most significant impact on the flow field. The flow field effect of the UR was optimal when the deflection angle was 30°, while the influence of deflection angle on the reefs at other positions was not significant. This study aimed to provide a reference for the layout design of UR.