Welcome to the third 2023 issue of Maritime Engineering in which we present three papers on the topics of wave overtopping, wave run-up and monopiles, respectively. The first paper seeks to provide a comprehensive analysis of the effects of sea level rise on wave overtopping rates in coastal areas of England, providing crucial insights for the according risk assessment. The second paper presents a new method of wave run-up prediction, intending to be applicable to the various types of natural beaches. The third paper aims to systematically quantify the monopile structural performance of offshore wind turbine and provide valuable insights promote design efficiency.
The first paper (Hames et al., 2023) presents quantitative evidence on the impacts of sea level rise on wave overtopping rates along the coast of England. The analysis, based on a national-scale flood risk analysis methodology, focuses on nearly 600 flood defensive assets, including vertical walls, shingle beaches, and sloping embankments. By applying a range of sea level rise scenarios, the study reveals a significant increase in wave overtopping rates compared to present-day levels. For lower return periods, the rate may be up to 150 times greater, and for higher return periods, up to five times greater. The study adopted a robust risk-based coastal flood risk analysis method. This approach involved multivariate extreme value modelling, which integrated historical sea level data, wave and wind conditions and a Monte Carlo dataset. A sensitivity analysis comparing nearshore and offshore approaches demonstrated the effectiveness of applying sea level rise to the nearshore for efficient impact assessments. These findings provide critical insights for coastal planning and flood defence design, highlighting the need to address rising sea levels and consider the non-linear relationships between sea level rise and wave overtopping. The study's methodology and results contribute valuable knowledge for policymakers, engineers and researchers, enabling informed decisions to mitigate and adapt to coastal risks associated with climate change.
The second paper (Villarroel-Lamb, 2023) provides a wide-ranging analysis of wave run-up prediction on natural beaches. The study reviews the existing empirical parametric models and evaluates the effectiveness of the Carimorph model, which was developed by the author of this paper. By calibrating the wave set-up and swash excursion components using site-specific conditions, the Carimorph model outperforms other parametric models in predicting wave run-up. The SandyDuck’97 coastal field experiment (CHL, 2009) has been adopted for calibration purpose. The model's adaptability through site-specific calibration leads to improved correlations between the predicted and measured wave run-up. This advancement in wave run-up prediction may be greatly beneficial to coastal engineering and management, offering a valuable tool for assessing hazards and developing erosion mitigation strategies.
The third paper (Nigitha et al., 2023) investigates the behavior of monopiles, widely deployed in fixed offshore wind developments, under one- and two-way lateral cyclic loading through a numerical analysis using Plaxis 3D. The numerical model has been calibrated and validated against the collected centrifuge test results. Parametric studies are conducted considering the effects of cycle numbers, load amplitude, and slenderness ratio on the behaviors of the monopile. The structural response including the accumulated displacements, cyclic stiffness, and load-displacement hysteresis have been achieved and analyzed. With the cycle numbers increasing, the accumulation of displacement rises and the cyclic stiffness of the monopile decreases. The load-bearing capacity may suddenly increase with an increase in length-to-diameter (L/D). The results provide valuable insights into the behaviors of monopiles under cyclic loading conditions. The findings may provide reference to promote better design efficiency and project reliability.
