Local scour around submerged square piles is very common in offshore and coastal engineering and can result in pile failure. In the study reported here, because the flow intensity (the ratio of the depth-averaged velocity to the threshold velocity for sediment particle motion) is one of the most important factors affecting the maximum scour depth in local scour, its effects on local scour around a submerged square pile were studied under clear-water scour conditions. A series of experimental tests with flow intensity in the range of 0.39–1.04 was conducted in steady current, and the flow intensity was classified as weak, transitional, or high according to the pattern of the scour hole upstream of the pile and the sand dunes downstream. The characteristics of sediment scour and deposition for temporal sediment bed elevation along a pile side and the temporal maximum scour depth were found to vary greatly among the three flow intensity conditions. An exponential function, which fitted the experimental data well, was used to fit how the maximum scour depth evolved, and the coefficients of timescale and scour depth proportion in the initial and development scouring stages were obtained at different values of the flow intensity.

In the context of global carbon neutrality goals and the transition to clean energy, ports have become a focal point due to their significant energy consumption and pollution emissions. This heightened attention has promoted research on green ports, with comprehensive evaluations of their environmental impact serving as a key driver of sustainable transformation. This paper presents a systematic review of 15 years of literature, uncovering key research directions and emerging trends in green port evaluation. It explores the evolution of evaluation methods and indicator systems tailored to diverse evaluation subjects. The findings highlight three key trends: segmentation of evaluation subjects, refinement of evaluation methods, and dynamic adaptation of indicators. By providing a comprehensive overview of the current evaluation practices, this study offers valuable theoretical insights and actionable guidance to support future research and facilitate the practical implementation of green ports initiatives.

Foundation scour is the erosion of sediments around pile foundations by wave and current in offshore wind energy. This phenomenon destabilizes foundations and poses a threat to pile safety. Therefore, scour protection becomes a crucial challenge in offshore wind projects. This paper reviews and synthesizes recent publications and patented technologies related to scour protection. Considering the primary engineering concerns, the paper proposes design principles for effective scour protection schemes to standardize evaluation criteria. These principles prioritize efficacy, independence, and cost-efficiency, enabling the analysis of scour protection scheme applicability. In addition, this paper summarizes and describes common protection schemes in the literature. The effectiveness of their protection is analyzed and summarized, and their economic and performance independence is evaluated. This paper categorizes flow-altering scour protection schemes found in the literature. Based on a comprehensive understanding of the mechanisms and engineering requirements of scour protection, the paper proposes a focus on determining the erosion reduction rate curve ($Ep-U/U_c$ curve) as a key criterion for evaluating the effectiveness of protection schemes under varying flow velocities and the erosion reduction rate of scour protection schemes under extreme conditions. The study highlights the necessity of establishing a comprehensive design evaluation methodology, which is crucial for addressing the significant challenges related to scour encountered in offshore wind power projects.

Laboratory experiments are carried out to investigate the hydrodynamic performance of a new pile-supported caisson breakwater with inclined porous plates. Reflection and transmission coefficients are analyzed for various wave and structural parameters, including incident wave height, wave period, plate porosity, number of layers, and plate arrangement. The results show that reducing the porosity of the porous plate can significantly lower the transmission coefficient. Additionally, increasing the number of plate layers enhances wave attenuation and reduces wave reflection. Furthermore, arranging the front layer with higher porosity and the back layer with lower porosity substantially improves the wave attenuation performance of the breakwater. In practical applications, optimal protection across a wide range of wave periods can be achieved by adjusting the porosity and arrangement of the porous plate. The findings of this study provide a valuable reference for the optimal design of pile-supported caisson-type breakwater with perforated porous plates in coastal protection engineering.

This article investigates the transmission coefficient of a novel pile-supported permeable breakwater featuring inclined porous plates under regular waves. To analyze the transmission coefficient, we propose a sectional method that involves multiplying the transmission coefficients of three distinct sections: the upper retaining wall and porous plates, the horizontal platform, and the piles. The calculation employs the eigenfunction expansion method and empirical formula for pile-supported breakwaters. This method is applicable for water levels that fall between the upper and lower edges of the horizontal platform. The analytical results are compared with experimental tests and show good agreement. Further analysis reveals that the transmission coefficient is significantly influenced by the increasing length of the horizontal platform. Moreover, it is observed that the effect of porosity ε is not particularly noticeable when ε>20%.

Liang, B.; Ma, S.; Pan, X., and Lee, D.Y., 2017. Numerical modelling of wave run-up with interaction between wave and dolosse breakwater. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 294–298. Coconut Creek (Florida), ISSN 0749-0208. Breakwaters play an important role in coastal disaster prevention and mitigation. In this study, a numerical modelling of the wave run-up on dolosse breakwater is set up by integrating the CAD software SolidWorks and the CFD software FLOW-3D. The breakwater is built with the lower porous media and the upper armour blocks (dolosse), which is different from the current approach that treats the whole rubble mound breakwater as porous media. The numerical wave flume has been validated by analytic solutions of Stokes wave theory. The computational results are in good agreement with the empirical formulas under different wave conditions. The model was then used to calculate the wave run-up over movable dolosse breakwater, immovable dolosse breakwater and porous media breakwater under various wave conditions. The comparison results show that the porous media model can not sufficiently reflect the real world. And the displacements of the dolosse will affect the energy dissipation and lead to smaller wave run-up. It suggests that the interaction between waves and the dolosse breakwater is important for the safety of the breakwater. Therefore, the presented numerical study provides a more reliable approach for simulating wave run-up on dolosse breakwater that can provide support for the design stage of breakwater.