Model experiment of hydrodynamic performance of square artificial reefs with hexagonal openings

In order to study the relationships between the resistance coefficients and lateral force coefficients of the square-shaped artificial reef with hexagonal openings and between the angle of attack and the opening ratio, we designed four model opening ratios (γ_ty = 0.06, 0.14, 0.25, 0.39) The resistance and lateral force of the rectangular open artificial reef at four kinds of attack angles (θ = 0°, 15°, 30°, 45°) were measured, and the resistance coefficient and lateral force coefficient were calculated. Hexagonal open square reef model resistance F_x (30°) > F_x (45°) > F_x (15°) > F_x (0°), and lateral force F_y (30°) > F_y (15°) > F_y (45°) > F_y (0°) were obtained; the reef model resistance F_x (30°) was 1.28-1.72 times that of F_x (0°), and the lateral force F_y (30°) was F_y (0°) 2.8 to 11.1 times. The angle of attack can have a greater impact on the resistance and lateral forces of the reef model. With 4 kinds of opening ratios and 4 kinds of attack angles, the resistance coefficient C_D ranged from 0.98 to 1.53. Resistance coefficient C_D (30°) > C_D (15°) > C_D (45°) > C_D (0°). The reef model resistance coefficient C_D (30°) can be up to 1.26 times compared to C_D (0°). At 4 kinds of opening ratios and 4 kinds of angles of attack, the lateral force coefficient C_L ranged from 0.001 to 0.21. The lateral force coefficient C_L (30°) > C_L (15°) > C_L (45°) > C_L (0°). The maximum lateral force coefficient C_L (30°) of the reef model can reach 3.5 times compared with C_L (0°). When θ = 30°, the effect of lateral force on artificial reefs cannot be ignored.