Study on the influence of cut-opening ratio, cut-opening shape, and cut-opening number on the flow field of a cubic artificial reef

Upwelling and back eddy are usually selected as obvious indices to study the characteristics of the flow field of artificial reefs. The influences of cut-opening ratio (OR), cut-opening shape (OS), and cut-opening number (ON) on the flow field of a cubic artificial reef were investigated. A Reynolds-averaged Navier-Stokes equation was established to solve the flow field of an artificial reef. Based on the finite volume method, the standard k-ε model was used to discretize the Reynolds-averaged Navier-Stokes equation. Flume model experiments were carried out to validate the accuracy of the numerical simulation. A multivariate analysis of variance was used to analyze the diversities of the OR, OS, and ON. The results showed that the upwelling velocities, including the maximum upwelling velocity and the volume-weighted average velocity, changed less with the above three factors. The ON and OR had prominent effects on the volume of upwelling and back eddy, while the OS had the least effect. A reasonable arrangement of ON and OR can enhance the field of upwelling and back eddy while an excessive OR or ON can weaken them. This study provided a scientific reference for the optimal design of cubic artificial reefs.