Journal of Waterway, Port, Coastal, and Ocean Engineering

Determining how to quantitatively analyze and evaluate a terminal layout is important for terminal design and construction organizations. In this study, a simulation-based quantitative analysis and an evaluation method were proposed to solve the comparison problem of water–water transshipment coal terminals. A simulation model that includes the seagoing ship-arrival subsystem, the yard operation subsystem, the barge arrival subsystem, and the performance indicator statistical subsystem was established. Based on the particularity of the loading and unloading operations of water–water transshipment coal terminals, the effect of the fluctuation in the seagoing ship-unloading efficiency and the barge loading efficiency on the operation of a terminal was considered in the model. Simulation models for three layouts of a water–water transshipment coal terminal were established. Simulation experiments were performed to analyze the future production performance of these layouts, and recommendations were provided for different goals. The application of the simulation model showed that the proposed method of the comparison and the selection for the design of water–water transshipment coal terminals is feasible. The method is also applicable to solving the problem of the selection of other types of terminals.

Extratropical cyclones (ETCs) are major storm, flood-producing events along the northwest European coastline. To evaluate the storm surge risk covering a return period over as many as 10,000 years (0.01% annual exceedance probability) in this region, a stochastic catalog was developed by perturbing historical European ETCs. Numerical simulation of the storm surges generated with an entire 10,000-year stochastic catalog; however, is computationally expensive. Also, not all the stochastic ETC events are flood-producing storms. We propose an efficient statistical approach to filter the stochastic catalog by estimating the storm-surge elevation and total water level at tide gauges and then selecting only the nonnegligible flood-producing coastal events. The proposed approach reduces the number of stochastic storms that need to be numerically simulated by 78%, thereby saving computational resources for high-resolution numerical simulations of flood-producing storms.

In this work, a computational fluid dynamics (CFD) model was coupled with a dynamic response model for simulating oscillatory and sliding motions of a composite caisson breakwater subject to impulsive wave loads. The CFD model was set up with the computational toolkit Proteus, which is a FEM-based software originally developed for solving generic transport equations. It has been recently used for simulating fluid–structure interaction within the context of coastal flows by using mesh deformation and immersed solid techniques. In this study, sliding and overturning of the caisson superstructure were modeled by coupling mesh deformation techniques with a dynamic model for the caisson motion response. Results were compared with experimental data and good agreement was achieved, given the uncertainties involved. These uncertainties were also assessed through a sensitivity analysis of the caisson, which demonstrated the importance of appropriate selection of numerical parameters and precise definition of the material and physical properties. Overall, the modeling approach further advances the state of the art in similar models by being capable of modeling random sea states while using a fully coupled approach for the fluid–structure interaction problem, which also allows the prediction of pore pressure buildup and uplift forces in the rubble foundation.

The angle of repose (AoR) of sediments is an important parameter in the hydraulics of sediment transport. This study investigated the AoR (ϕ) of submerged cohesive sediments using a tilting plane. The results indicate that the yield stress and particle size are factors that have major influences on the AoR. For specific sediments, sin(ϕ) increases linearly with increasing yield stress. For a certain yield stress, the AoR increases with increasing median grain size. Meanwhile, the effect of the yield stress on the AoR is significant for the cohesive sediments and becomes progressively weaker with the increasing median grain size. A simple and reliable empirical formula that includes a rheological term and a gravity term is proposed to calculate the AoR of submerged cohesive sediments. Furthermore, a series of vibration tests was designed and performed with the sediment samples to explore the effect of mechanical vibration on the AoR. The results show that the mechanical vibration can significantly fluidize the submerged cohesive sediments, which can lead to a significant decrease in the AoR.

The study addresses the question of the possible design benefits when considering the interaction between a modern marine modular rubber fender and a steel tubular pile substructure of a berthing dolphin. Absorption of the berthing kinetic energy of the vessel by a dual-elasticity pile-fender berthing system is described in detail using the interactive treatment method (ITM). Application of the ITM is illustrated by a calculative example, assuming a 37,700 deadweight ton (DWT) tanker as a berthing ship, realistic geometries of large-diameter steel piles of the berthing dolphin substructure, and a family of Sumitomo $\pi \left(\mathrm{Pi}\right)$-type modular rubber fender units. By splitting the berthing kinetic energy into two parts absorbed by two elastic component elements of the dual-elasticity system of the berthing dolphin, the ITM is an effective tool for proper selection of the minimum required size (i.e., outside diameter and wall thickness) of steel piles of the berthing dolphin substructure in relation to the size of fender unit assumed. Finally, using ITM, an example analysis is performed to illustrate the influence of fender size selection on the berthing force, and the mass and stiffness of the steel-pile substructure of the berthing dolphin, as meaningful parameters influencing the most economical solution in the berthing dolphin design.

Offshore jacket platforms are of great importance due to their roles in shallow water areas, such as the Persian Gulf. Building infrastructures are always a challenge for engineers because of uncertainties in different aspects. Using an experimental model is an essential technique for reducing uncertainties. However, using experimental data adds other uncertainties to the problems and dealing with them can play a key role in project applicability and success. Uncertainties in every engineering problem can be classified into three distinct groups related to the computer model: (1) numerical uncertainty, (2) parameter uncertainty, and (3) structural uncertainty. Among these categorized uncertainties, the second and the third ones are considered for the case study of this research. In this study, model parameter uncertainties and the structural uncertainties have been considered simultaneously. This approach is applied to a three-dimensional (3D) fixed offshore jacket model (SPD9 located in the Persian Gulf) for the first time in the offshore structure field, both numerically and experimentally. Disagreements between the numerical model predictions and experiments are reduced by considering the calibration of model uncertain parameters and a discrepancy term, which is defined by a mathematical function for a real project. Therefore, the main benefits and innovations of the methodology can be stated as (1) using experimental data through modal analysis of a 3D steel offshore jacket platform for numerical model updating and (2) developing a previously studied method through reducing parametric and structural uncertainties simultaneously. The results express the success of considering parameter uncertainty and structural uncertainty for the previously mentioned case study by decreasing the disagreements between experimental data and numerical simulation. The results also indicate the importance of considering a discrepancy term in the calculation phase as a model form error term due to increasing the applicability of the proposed method for an offshore jacket platform.

The influence of grain size on sediment transport during the initial stages of dam break–type flows over horizontal mobile sediment beds was investigated through dimensional analysis and experiments. A new dimensional analysis reconciles the unbalanced dimensions in Bagnold’s formulations describing the grain size influence on steady-flow sediment transport and indicates that the sediment transport is inversely proportional to the square root of the grain size, consistent with Bagnold’s empirical correlation. Total transport rates were measured for quartz grains ranging from 0.22 to 2.65 mm in diameter. Regression between the dimensionless variables indicated that the mobility number collapses the sediment transport data better than the Shields number and indicated that the total sediment transport is approximately inversely proportional to the square root of the grain size and the velocity to the fourth power. The Meyer-Peter Müller transport model based on the Shields number requires transport coefficients for the finest sand that are significantly larger than the conventional values suggested in the literature, between 30 for k_s = 2.5D₅₀ and 40 for k_s = D₅₀. The values for other sediment sizes are closer to conventional values, within the usual range of 10–12 for k_s = 2.5D₅₀, but somewhat higher at 16–22 for k_s = D₅₀. The occurrence of sheet flow in a suspension regime appears possible, which may explain the significantly larger transport coefficients required for the finest grain size.

This paper presents a simplified analytical approach, based on power transmission theory, to estimate the transmission coefficient of a floating box structure with finite width. In evaluating the transmitted wave power, this approach considers both the incident wave power and the heave oscillation of the floating structure. Additional power due to the acceleration of the floating body and the hydrodynamic mass increases the transmitted wave power behind the floating structure and consequently increases the transmission coefficient. The proposed theoretical approach was validated using laboratory-scale experimental data obtained from the literature for floating breakwaters and wave energy converters. The results of the proposed approach were in good to excellent agreement with those of experimental studies. In addition, the reliability of the present model was assessed by comparing its results with those of other theoretical approximations. The effects of sea depth, relative draft, and incident wave height on the magnitude of the transmission coefficient distinguish the proposed model from others in the existing literature.

Rapid landslides into water bodies may generate massive water waves posing a threat to riparian settlements and infrastructure. These waves are referred to as impulse waves and exhibit tsunami-like characteristics. The generation and, in particular, the spatial propagation of impulse waves were studied in a hydraulic laboratory wave basin. A videometric measurement system was applied to track the water surface displacement. Compared to fixed wave gauges typically applied in previous studies, this technique yields a quasi-continuous representation of the water surface, allowing for a detailed analysis of spatial propagation patterns. In total, 74 experiments with deformable mesh-packed slides were conducted, thereby varying the slide impact velocity, slide mass, slide thickness, slide width, slide impact angle, and still-water depth. Empirically derived prediction equations are presented and discussed for key wave characteristics, including wave amplitudes and celerities. In the context of a preliminary hazard assessment, these equations allow for the estimation of wave magnitudes at prototype scale.