Numerical study of local scour around a cubic artificial reef in steady current

Local scour poses a risk of artificial reefs (ARs) capsizing or being buried. However, there is currently a lack of effective research methods to explore the mechanisms. This paper studies the scouring process of a cubic AR under steady flow conditions using a combination of flume tests and numerical simulation methods. The scouring results were numerically simulated using the RANS equations implemented with the RNG k-ε turbulence model in FLOW-3D software, demonstrating a strong correlation with the experimental data. Subsequent numerical simulations were performed to analyze the influence of flow velocity, sediment grain size, and opening ratio on scour depth and topography. The study revealed that the maximum scour depth is in the front corners of the AR. Among the three influencing factors, flow velocity exerted the most significant influence on both the depth and volume of local scour, followed by sediment grain size and opening ratio. Moreover, the scouring intensity around the AR increased with higher flow velocities, smaller sediment grain sizes, and a smaller opening ratio. •The maximum scour depth is at the corner of the upstream surface.•Suspended sediment morphology varies with opening ratios of the artificial reef.•The depth of scour exceeds the sediment accumulation height.•Flow velocity most significantly influences local scour depth and volume.•Low velocity, large grains, and large opening ratio reduce scour intensity.