Three-dimensional numerical simulation on flow behavior behind trapezoidal artificial reefs

Abstract

A series of three-dimensional numerical simulation is performed to investigate the hydrodynamic behaviors around a single and two trapezoidal artificial reefs. The attack angle i is varied from 53.1° to 76.0° and the opening ratio φ is varied from 0 to 0.4. The results show that the attack angle and opening ratio have significant effects on the hydrodynamic behaviors of an artificial reef rather than the incoming flow velocity. With the increase of cot (i), the upwelling region and wake region indexes gradually decrease. The upwelling region indexes increase with the increase of incident angle θ. At θ ≥ 45°, the upwelling region indexes decrease with the increase of center-to-center spacing distance D/L and the flow interference between two reefs becomes weakened. At 1.5 ≤ D/L ≤ 2 and 75° ≤ θ ≤ 90°, the large volumes of the upwelling region and wake region are observed. Comparing to the single artificial reef, the upwelling region and wake region indexes of two artificial reefs increase, the maximum upwelling region height and volume of two ARs are increased by 14.9% and 48.4% at θ = 75° for D/L = 1.5, respectively, indicating the optimized configuration for the hydrodynamic behaviors of two trapezoidal reefs.